The 100th episode of Chicago PD was explosive.

Platt was gearing up for her first morning TV interview, which was a big team thanks to her hubby Mouch, who was even hosting a "watch party" for his girl. 

But a few seconds into her interview, viewers heard an odd beeping sound and then a bomb exploded, sending Platt and the anchors flying on national television.

PD and Fire are on the scene within minutes, with Mouch desperately checking each ambo for signs that his wife survived. 

Inside the station, Platt regains consciousness and manages to pick herself up to check on the anchors, both who have been badly burned. 

She pulls one of them into the breakroom, where she applies a cold compress to her burns and waits for help. 

Soon enough, Severide busts in through the door and pulls the women out, much to Mouch's relief. 

Not so relieved? Intelligence, as they have a long night ahead of them. 

On the way to the hospital, the burn victim uses her last few breaths to tell Antonio about a suspicious package that arrived for her a few hours before the bombing. 

Her story checks out and furthermore, they realize someone had been sending Sherri several threatening messages all of which told her to "burn in hell."

According to the station's visitor log — this explains why they have one — the package was brought in by an entertainment journalist named Eric Mitchell. 

Some of the detectives head to Eric's place to question him, but as they approach, he opens his mailbox and is blown to smithereens. 

He can't be the suspect when he just became the victim, right?

The clever bomber used Mitchell's name to sign in and led PD to him. 

Fire confirmed both bombs hail from the same creator and the only thing that's traceable is the military grade C4, which was either stolen or bought on the black market. 

Determined to get to the bottom of the case, Voight orders his team to find some nexus between Mitchell and Sheri but they can't seem to find anything. 

Desperate times call for desperate measures and Antonio suggests they post a photo of a man that was hanging around the vicinity and matched the description — white with a beard — and although some are against it, Voight allows it. 

Shortly after the post goes up, the public identifies him as Mark. Aside from fitting the profile, he was in the military which means he'd have knowledge of how to make an IED, went to school with Mitchell and worked briefly as a security guard at Sheri's station. 

All signs pointed to him being their guy so Intelligence violently apprehended him in front of his daughter. 

However, Mark insisted he was innocent and one of his closest friends said Mark actually protected Sheri from some hot-headed visitor obsessing about a gossip blog.

Back at the station, Platt prematurely returned to work and found a suspicious package with a threatening note attached to it.

Expecting the worst, the station evacuated and the bomb technicians eventually confirmed it was a cheap IED made by the same person but so hastily, it wouldn't have gone off. 

That puts a dent in the Mark theory given he was in lock-up when the bomb was delivered.

The note was a vendetta against "fake news perpetrators," which meant it was a personal attack.

During her time in college, Sheri ran a gossip column called "Chicago Scoop," which falsely suggested that Mitchell was the killer in a murder investigation he was reporting on because he seemed "obsessed" with the victim. 

After news broke, the outlet fired him. His former co-workers admitted the claims were nonsense, but even after he was cleared, they fired him anyway because it was bad PR.

The false allegations made through a 140-character tweet aka "fake news" blew up his career and his personal wife as his wife left him and later committed suicide. It also got Sheri killed. 

Intelligence checked out his place and while they didn't find any bomb-making materials, they did find his obsessive and very detailed web, which lead back to Sheri. 

He managed to clear his digital footprint, leaving behind only a video explaining his attack and saying "journalism needs to be held accountable."

The detectives pinpoint nearly a dozen potential next victims but given that they are still several steps behind him, they're probably already too late. 

Olinksy's informant leads them to the seller of the C4, who turned out to be Leer, the man they met shortly after Mitchell was blown up. 

With this new evidence, Antonio is forced to let Mark go and doesn't even have it in him to apologize. 

He eventually realizes that what Sheri did to Shepard and what he did to Mark and his own daughter, Ava, are not that different.

He grounded Ava for posting pictures from some party when she was supposed to be studying and having two social media profiles. Eventually, he realized he'd misjudged her and the situation and didn't even give her a chance to provide her side of the story which was that she was going to pick up a drunk friend. 

With Ava, the damage was reversible, but things with Mark were much uglier as people were still wrongly blaming him and even throwing bricks through his window, which injured his daughter. 

The lesson here — everything on the internet is permanent. 

Upton finally figured out a way to get ahead of Shepard by using Leer but warned the Sarge that it was "unorthodox." Ha, please — that's Voight's middle name! 

The detectives reach out to Chicago Fire for an assist. 

Brett and Dawson — Antonio's on-again-off-again girlfriend and sister, respectively — have responded to Leer's house on multiple occasions for his heart condition. 

Voight needed them to gain access to the house so they could clone his laptop and stop Shepard without triggering him. 

The Chief hesitated at first but both ladies were on board to do anything to help. 

Part two continues on Chicago Fire Season 6 Episode 12.