(Disclaimer: I do not own Criminal Minds or its characters)

Thanks to fishtrek, Caroliny Hotchner, Cherubim22, R Leaf, livvy1843, and pallyndrome for reviewing the last chapter.

Enjoy.

Rossi and Hotch stared back at Morgan, both sharing a similar look of confusion. Dave was sat down, his hands gripping the arms of the chair tightly but Aaron hadn't even managed to take a seat.

"Reid's dad?" Aaron asked and Morgan nodded. He had started to sweat, all of his explaining was making him doubt himself. "You think he attacked Reid?"

"Without a doubt," Penelope said and her voice squeaked.

"And that he is responsible for the attack on Joe, Wally and Bailey?"

Morgan nodded and to his surprise so did Rossi. The old man was looking more grim than before.

"Maybe Reid's Dad is attempting to copy-cat... maybe that's why he attacked Reid, he might have got in the way of his plans."

"Uh... that's not exactly what we're saying," said Garcia.

"You still don't think he's your son?"

Dave looked up at Morgan and he pressed his fingers to his temple.

"I don't know... I thought..." he shook his head. "I should never have got my hopes up. You could be right though, Reid's dad could be the copycat."

"Or the real thing," Emily muttered.

Aaron shot her a look. "So you believe this too?"

"We found some more things while you were gone," said Emily and she grimaced. "William Reid could be the original killer here."

"Go on then," Dave said in a low grumbling voice. "What has you so convinced."

"Alright." Emily turned to the second laptop JJ had got them and pulled open two tabs. "This is your son's birth certificate," she said, motioning to the one on the left. "This is Reid's."

Rossi glanced at them for a moment. They both had different dates, confirming his son was younger than Reid.

"Neither certificate is fake. That means they are two separate people," Morgan said.

Dave looked across at Aaron and he shrugged. "You're not proving anything."

Morgan raised his head. "They are two people. There's William Reid Jr. and Spencer Rossi. Rossi, could you positively identify your son after he was killed?"

Dave paused and sat uncomfortably for a moment. He wet his lips and muttered, "no."

"Because he was too badly burnt and the unsub had removed all his teeth," Emily said and she grimaced at the look of horror on Rossi's face. "There was no real knowing of who that child was."

Rossi started to shake his head. "My son didn't come home like the other boys. He was the only child left there, that was his body."

"Sir, did you read the coroners initial report?"

Rossi's gaze flicked down to the computer screen broadcasting Penelope. "Y-Yes," Rossi said, stumbling over his words slightly.

"The coroner believed the child to be four or five," she said quietly. "Your son was only three a-and you said yourself that he was small for his age."

Rossi tried to open his mouth but he couldn't manage to pry it open. He couldn't remember the coroner's report. He only remembered knowing his son hadn't come home... knowing there was only one boy left in the basement and only one body found there.

"William Reid Jr. would have been five," Garcia said.

Rossi still couldn't speak. He looked at Morgan and then Emily. Emily looked away and JJ spoke up instead.

JJ's voice was soft when she spoke and she turned her attention to Aaron. "Hotch, do you remember anyone else there? All the kidnapped boys talk about a man and a wife... Wally, Joe and Fraser mentioned a kid from upstairs in their statements-"

"Oh god." Aaron's hand flew to his forehead and he found himself sinking into the chair closest to Rossi. "Oh my god."

"Aaron?" Dave looked across at Aaron who's gaze was too distracted with thought to notice him.

JJ exchanged a glance with Morgan and Emily before she stepped closer to Aaron.

"You do remember?" she murmured and Aaron nodded.

"I-I forgot about him," he mumbled and he turned to Dave. His eyes were wet. "Spencer was helping to keep a lookout for him and the unsub when we got out. He was this kid who lived upstairs, he came down with a gun a couple of times when I was there, threatened to shoot us. W-we thought he was meat- the unsub's son. I-I never thought..."

There was a long silence then while Aaron sat shaking his head, his eyes welling with tears.

A pinging sound came from Garcia's phone just as Aaron sat upright.

"Uh... guys. They finished the paternity test."

"What? That was fast..." Dave slowly turned his head to Aaron and he frowned. "I only agreed to it when we were at the hospital."

"I hadn't ordered one..." Aaron muttered and he looked at the screen holding

Penelope who was smiling sheepishly.

"Does it matter who did what? Or who had the FBI database cross blood samples between you and Reid... okay, I'll stop talking now." Penelope moved sheepishly back from her camera for a moment.

The team looked at Rossi, waiting for his to shout but instead he sat up straighter and he started to speak rather calmly. "Well... what does it say?" he asked.

Bailey say in the dark mumbling things to himself even he was unsure of. Quiet words of encouragement in a situation he knew the end to.

He wasn't sure how long Spencer had been gone. He had heard screaming downstairs sometime after William's car had left and come back. It had been quiet for hours since then. Bailey would like to have thought it was days since but the sun had gone down and was on its way back up when William entered again.

Bailey who had started to drift off with the help of his mumbles jolted upright. He tried to rub at his eyes which were blurry with sleep but his arms refused to budge.

Bailey stared at William as the man approached. He expected him to be grinning but instead William was pale, his mouth a thin line of grimness.

Bailey tried to speak but his words croaked out and he swallowed quickly, flinching when William drew near.

Finally, Bailey found his words. "What did you do to him?" he asked, his voice weak and raspy. He glanced at the spot where Spencer had been and William followed the gaze. His eyes stayed there for a moment and Bailey looked at the older man with a frown.

"He's been taken care of," William muttered.

Bailey had known this before William had even entered the room but despite this he felt his fists clenched with rage.

"He was your son!" Bailey snapped, his voice croaking harshly. He cleared his throat as William looked back at him. "How could you kill your own son?"

"He wasn't really my son," William said and his voice shocked Bailey out of his anger. It was so quiet and vague that Bailey wasn't sure this was the same man who had dragged Spencer out many hours earlier with a lethal grin on his face.

William looked Bailey up and down.

"I need to get another before I dispose of you," he grumbled, more to himself than to Bailey.

The names of many of the other kidnapped boys came to Bailey's mind and he glared up at William. "Good luck," he said.

William finally smiled then. His pale lips cracked upward slightly. "I don't need any luck," he said. "You're all as weak as you were back then."

William was about to walk away when Bailey recalled what Spencer had said to him and it was his turn to smile. "I'm sure you'll need all the luck you can get with the FBI closing in," he said, his voice growing stronger. He coughed again and grinned wider as William turned his head back toward him. "Your son told me all about his career. You must be proud to have an FBI agent as a son."

If William hadn't been pale before he certainly was now.

Bailey continued. "And as soon as they identify him as your son and find where he's been staying, they'll come here. His whole workforce. A team of FBI agents at your doorstep."

William stared back at Bailey as the young man chuckled to himself. Williams's breath was shaky all of a sudden and he glanced for the door.

"How longs it been now? They probably found him a while ago." Bailey pressed his lips together and looked over at the sun shining through the window. "Oh I'd say they're on their way here now."

William wanted to argue, wanted to smirk and reveal his actual plan but... he hadn't thought about Spencer being an FBI agent. The FBI were already here, he knew that from the news reports and the talk around his office. They were already treating his recent attacks as a kickstart back into the cold case of 86. William looked blankly down at Bailey who was still smiling to himself. The kid was probably right, they'd be here to ask him questions before long regarding his dead son... and... William shook his head, pressing his palms against his eyes. He knew he was inexperienced but this was just sloppy.

"Whatcha gonna do now?" Bailey asked with a cocky smirk.

William pulled one hand away from his eye and looked toward the door. The FBI would be right on his trail. He didn't have time for this kid anymore.

William turned on his heel and yanked open the attic door.

"DIANA!"

It wasn't Dave who stormed out the conference room.

It was Aaron.

"Hotch!" Morgan was on his feet and hurrying after his unit-chief. The rest of the team were still in shock. Rossi was slumped down in his seat, his elbows balancing on his thighs while he smiled broadly into his hand.

He had to call Erin. He had to tell her he was Reid's father... that they were his real parent. She needed to know their son was alive... that he'd been with them all along. Rossi snorted slightly into his palm and tears sparkled in his eyes. Erin had always said that Spencer was around them, that she felt it. Dave humoured her spiritual ideas but he never thought she'd be right; that they had been working alongside their own son for years.

"Hotch?"

Dave looked up to see his team on their feet, looking out through the windows. Dave sniffed and lifted his head from his hand. He laughed as he wiped his eyes.

Meanwhile, Morgan had caught up to Aaron and was pulling him back.

"Where are you going!?"

Hotch stopped to glare back at Derek. "Reid's dad. You're right," he said darkly. "And I'm going to kill him."

Aaron yanked his arm from Derek and he turned away again.

"I can't let you do that."

Aaron grit his teeth and turned around. He was surprised to see Emily and JJ there too and Rossi a little way back, shaking his head to himself and smiling.

Aaron focused on Derek who looked just as angry as him. "This isn't your fight, you can't understand but I have to do this."

"I understand plenty," Derek said and he pulled his gun from its holster. "I'm not going to stop you. I'll hold the bastard down for you if you need me to. But you're not going alone."

Aaron didn't smile but he nodded at Derek.

"Uh... I'm not sure-" JJ started but Derek and Aaron were already hurrying out the front doors. She turned to Emily who was starting after them.

"Come on."

Dave watched his team leave, JJ grabbing some vests before she too was out the door.

"What's going on there?"

Dave turned and saw Penelope's anxious face looking back at him from the laptop. He smiled and retook his chair in front of her.

"I think they've gone to check Reid's d- William Reid's house."

Garcia nodded and she looked awkward for a moment before she said, "I'm sorry. I should've waited for you-"

"Stop."

"I... but... Sir?"

Rossi smiled warmly and he pulled his phone out of his pocket. "I should call Erin."

Penelope's eyes grew wide and she nodded quickly. "Of course, right...Yea, sorry."

Rossi chuckled and felt tears come to his eyes again. "Penelope..." he paused as a watery smile possessed his lips. "Thank you."

Thanks for reading.

It got a bit soppy at the end there but next chapter will be pretty cool (I hope.)

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See you soon, stay safe.