In “Bones” Season 12, episode 4, the Jeffersonian-FBI team learn that Booth’s life is in danger. Kevin Estrada/Fox

Remember when Seeley Booth (David Boreanaz) told Dr. Temperance Brennan (Emily Deschanel) about that time that he shot a Bosnian warlord at his son’s birthday party? He was a sniper in an Army Unit. Well, “Bones” Season 12, episode 4 called back to that event.

The murder victim in “The Price For The Past” is none other than Aldo Clemens, the priest who married Booth and Brennan. In the past few years, all of Clemens’ demons have come back to haunt him. He became a heroin addict prior to his death. He even got fired from his bartending job after he was caught stealing from the cashier in order to finance his addiction.

Throughout “Bones” Season 12, episode 4, we are reminded that Booth could have been Clemens had it not been for Brennan. They both became addicts and the both care about their loved ones a lot. Booth regrets not doing enough for Clemens.

Brennan encourages her husband to seek justice for his dead colleague but only within the purview of the law.

The Jeffersonian swabs Clemens’ needle marks and runs the heroin residue through their existing database of dealers. However, when Booth visits the dealer, it’s clear that he isn’t the murderer.

Fortunately, the victim had a combination of chemicals typically found in a recording studio. He was being held there against his will. It also becomes clear that Clemens’ murder was planned. Brennan notes signs of torture on the victim’s body. Apparently the killer used an old Middle age form of torture that required rats to dig in to the victim’s ribcage while he’s still alive. Yikes.

Booth and Brennan visit the abandoned studio and take a few photos before realizing that the place is packed with bombs. The couple makes it out just in time. The explosion would have surely killed both of them.

Fortunately, Booth was able to find a skull’s x-ray before the studio blew up. It belongs to the Bosnian warlord that he shot way back in the past. Now his son is out for revenge. That’s right: Booth’s life is in danger.

“Bones” Season 12 airs Tuesdays at 9 p.m. EST on Fox.