A month before Gabriel’s attack, Elaine visits her dad in prison and learns he has stage 4 lung cancer. She reacts coldly to this news and keeps asking him why he asked her there. He ultimately says he wanted to apologize.
The next day, Elaine’s having sex with Gabriel in the station’s bathroom. She says she thinks she loves him; he says he loves her, too. As soon as Gabriel leaves the restroom, he’s informed they’ve found a body. It’s the first victim of the acid murders.
Around this time, the station also gets a call from Isaac Taylor reporting his colleague Jonas Borner as missing. The night before, Borner left Taylor a voicemail that concluded in guttural screams. Later, Gabriel discovers both Taylor and Borner have a restraining order against former patient Richard Bell, who was released from prison the week prior. Believing Bell is the acid killer, Gabriel finds and arrests him.
While Bell is in their custody, another victim of the acid murders appears. The forensics team notes that the murder happened in the past few hours, meaning Bell couldn’t have done it. Gabriel orders to let him go.
Earlier, Jonas had been calling Taylor as he gets in his car after a drunken night out. Once in the vehicle, someone in the backseat covers his head with a plastic bag and slits his throat. It’s Elaine.