In the next episode of "Criminal Minds," the Behavioral Analysis Unit (BAU) led by Emily Prentiss (Paget Brewster) race against the clock to catch a stealthy killer who uses hi-tech drones to murder his victims.

The trailer for the upcoming installment titled "Killer App" was recently released and showed Prentiss telling an agent the seriousness of the case. "This unsub [unknown subject] has killed almost seven people," she said chillingly. Apparently, the killer uses military drones in strikes to take down enemy targets. The murderer's back is shown as he inspects and fixes his state-of-the-art killer drone. These devices prove to be stealthy as one is shown going downwards and looking inside the back of a car.

The case takes a turn for the worse when Prentiss accuses a manager for something that could turn the whole thing upside-down. "Did you employ a serial killer?" she asks the manager. However, he calmly replies, "That information is confidential." It remains to be seen if the killer is being employed by a shady company and if the BAU will be able to stop the killer just in time before he claims another victim.

In the last episode, Matt Simmons (Daniel Henney) almost met his end when the killer Gabriel Merza (Solomon Shiv) jumped him and had his knife to his throat. Fortunately, he was able to push off the knife and was saved by his backup team. Prior to his capture, Merza killed a number of men who were clients of his prostitute daughter Kimberly Desmond (Jamie Gray Hyder).

Merza could not stand his daughter being in the sex business that he tortured and killed those men she was involved with on many nights. Desmond was liberated nonetheless by Merza's arrest.

"Criminal Minds" season 13 episode 4 will air on Wednesday, Oct. 18 at 10 p.m. EDT on CBS.