Chicago P.D. Episode 3.06 You Never Know Who's Who

Burgess (Marina Squerciati) and a temp partner investigate reports of a suspicious parked car. Upon closer examination, they find that the driver is dead, the car is bulletproof and that the dead man is one Victor Cullen. After entering his house to search further, the unit finds a stash of over a million dollars in cash... and hundreds of weapons.

After linking the weapons to several unsolved crimes, the unit discovers a tangled web of deception and would-be espionage. Turns out, Cullen has been passing himself off as a CIA operative, and hiring men - unaware of Cullen's plot - to assassinate criminals the C.P.D. was unable to keep behind bars. After tracking down the pseudo-CIA operatives - and with a little help from Olinsky (Elias Koteas), who poses as a CIA agent - the unit is able to remove Cullen's team from the streets.

Desk Sgt. Platt (Amy Morton) is able to help Ruzek by interceding with the special investigator of his case. Ruzek is reinstated, and his case is closed.

Olinsky receives the results from the DNA test (to determine if he is Michelle's father), but decides to rip up the envelope before learning the truth.

Lindsay tells Halstead that their tryst on the couch was a one-time deal... but by episode's end they take their relationship public, holding hands and sealing the deal with a kiss at Molly's.