Index Case
S4 episode 3 Aired on July 17, 2016

Warning: Contains Spoilers

Victim: Chris Mancuso, environmental impact researcher

Killer: Dr. Logan Tenwick, breast cancer researcher

The Discovery: Chris is found in a sensory deprivation tank with an odd chemical smell. After returning from a surveying trip in Chile, he went to his regular appointment at the spa to help with the jet lag.

The Squad: After asking a suspect for his autograph and then apologizing for arresting him, Det. Mitch Kinecki is being transferred to Telephone Response to work on his people skills. Det. Angie Flynn can honestly say the place won’t be the same without him. Staff Sergeant Oscar Vega pulled strings to get hotshot detective Det. Paula Mazur. (He also suggests Angie stop using the motor pool cars for personal use – she still hasn’t replaced hers since Neville Montgomery had it firebombed.)

Investigation: Dr. Betty Rodgers finds evidence of ammonia mixed with bleach. Someone set the cleaning cycle to start while Chris was still in it, turning the isolation tank into a gas chamber.

When Dr. Rodgers gets the full lab results back, they contain something unexpected and she immediately declares Code Orange and quarantines the morgue. She and Chris’ body test positive for whatever it is he brought back from Chile, but the rest of the team is in the clear.

Det. Brian Lucas notifies Chris’ girlfriend, a brilliant molecular biologist named Kierra Graff, about his death. Kierra works for Dr. Logan Tenwick at Turner Bio Science. After they get the news, Dr. Tenwick goes home, where his symptoms worsen.

Later, Kierra collapses at work and falls into a coma. She didn’t see Chris after he got home, but she did see Tenwick. Dr. Tenwick’s boss and five other people come down with the virus and are quarantined. One of the original cases in Chile dies and the CDC works to ID the virus as Dr. Rogers is forced to hunker down in the lab slowly getting sicker.

In the squad room, Lucas suggests Kierra might be having an affair, then has to fork over $20. (The detectives established an Affair Jar. A mention costs $20, but if the motive actually is an affair, the person to suggest it wins.)

The detectives track coded emails to a dead drop at the library and pick up an environmental lawyer who says Chris was feeding her info on his boss’s corrupt business practices.

As the investigation continues, six new disease cases crop up around town and they think it’s the killer spreading the virus. The clock is ticking. They realize that Dr. Tenwick hasn’t been at work and wasn’t tested and serve a medical warrant at his house, but he’s not there.

Oscar brings Betty food at the morgue and she collapses, so he breaks quarantine and rushes to her side. He’s just exposed himself to a deadly pathogen but Betty sees the scientific potential: they can track Oscar’s early progression to ID it.

There’s a report of a pharmacy robbery; it’s Tenwick trying to steal anti-retroviral drugs. Angie and Paula suit up and find Tenwick near death nearby.

Finally Betty gets good news: the virus has been identified as a mutated form of MERS.

Background: Chris prepared a report on land in Chile that Dr. Tenwick wanted to use for a lab, saying it was a protected marshland and not viable. Tenwick was struggling to meet a deadline to present to the Board and Kierra offered to help him. Tenwick didn’t like that Kierra was dating Chris, then he finds Kierra’s letter of resignation on her computer and blames Chris, thinking he’s robbing the world of her gift.

The Motive: Dr. Tenwick stopped Chris as he was going into the spa to urge him to break up with Kierra. Chris tells him to back off or he’ll go to the Board of Directors and Tenwick worried a false allegation would turn the Board against him and end his work.

As Tenwick is confessing to Angie from his hospital bed, Kierra walks into his room (she’s recovered, too) and tells him that she was going to quit because Tenwick’s research theory was wrong. She was going to go to the Board but Chris convinced her not to ruin Tenwick’s career. Kierra wasn’t leaving because of Chris, she was leaving because of Tenwick.

Angie celebrates the closure of the case and the fact a virus nearly wiped out half the city by finally replacing her firebombed car.