Child's Play 3

In 1998, eight years after the previous film, The Play Pals (Good Guys) has recovered from bad publicity brought along by Chucky's (voiced by Brad Dourif) murder spree. The company releases a new line of Good Guy dolls and recycles Chucky's remains. However, the soul of serial killer Charles Lee Ray still inhabits the remains, and Chucky is soon revived. Chucky is unwittingly given to Play Pals' CEO Mr. Sullivan, whom Chucky kills. He then uses computer records to relocate Andy Barclay (Justin Whalin).
Still troubled by his past encounters with Chucky, 16-year-old Andy Barclay (Justin Whalin) has been sent to Kent Military Academy after having failed to cope in several foster homes. Colonel Cochran (Dakin Matthews), the school's commandant, begrudgingly enrolls Andy, but advises him to forget his "fantasies" about the doll. Andy befriends cadets Harold Aubrey Whitehurst (Dean Jacobson), Ronald Tyler (Jeremy Sylvers), and Kristin DeSilva (Perrey Reeves), for whom he develops romantic feelings. He also meets Brett C. Shelton (Travis Fine), a lieutenant colonel who routinely bullies the cadets, especially Andy.
Shortly after Andy arrives, Tyler is asked to deliver a package to his room. Tyler realizes that the package contains a new toy and, excited, takes it to the cellar to open it, only to have Chucky burst free from the package. Remembering the rule that he can possess the first person who learns his true nature (and that with a new body, it need not be Andy) he tells Tyler his secret, but just as Chucky is about to possess him, they are interrupted by Cochran, who takes the doll away. Cochran throws Chucky into a garbage truck, but Chucky escapes by luring the driver into the truck's compactor and crushes him. That night, Chucky attacks Andy and tells him his plans for taking over Tyler's soul. But before Andy can attack Chucky, Shelton comes in and takes the doll from him. Andy tries to get the doll back by sneaking into Shelton's room, but Shelton catches him in the act. Upon realizing the doll has vanished, Shelton suspects it stolen and forces all the cadets to do exercises in the courtyard as punishment.
Andy unsuccessfully tries to warn Tyler about Chucky. At one point, Chucky lures Tyler into playing hide-and-seek in Cochran's office, where he attempts to possess the boy again. However, they are interrupted by De Silva and, moments later, Cochran himself. When the cadets leave, Cochrane is suddenly confronted by a knife-wielding Chucky. The resulting shock causes Cochran to suffer a fatal heart attack.
Despite Cochran's death, Sgt. Clark declares that the school's annual war games will proceed as planned, with Andy and Shelton on the same team. However, Chucky secretly replaces the paint bullets of the Red team with live ammunition. When the simulation begins, Chucky accosts Ronald, then threatens the boy when he refuses to take part. Ronald stabs Chucky with a pocket knife and flees, trying to find Andy. Chucky then attacks Kristen and holds her hostage, attempting to lure the teams into fighting each other to save her. Chucky forces Andy to exchange Kristen for Tyler.
Suddenly, the Red team descends upon the area and obliviously opens fire with their live rounds. Shelton is killed in the crossfire. Amidst the chaos, Tyler makes a quick getaway, but before giving chase, Chucky tosses a live grenade at the quarreling cadets. Recognizing the danger, Whitehurst bravely leaps on top of the grenade and sacrifices himself to save the others. With no time to mourn his friend, Andy heads off in pursuit of Chucky, with Kristen close behind.
Eventually the chase leads the group into a fake haunted house at a nearby carnival. Ronald tries to get a security guard to help him, but Chucky kills the guard offscreen and kidnaps Ronald. In the ensuing melee, Chucky shoots Kristen in the leg, leaving Andy to fight Chucky alone. When Tyler is inadvertently knocked out, Chucky seizes the opportunity to possess him, but Andy intervenes, shooting him several times. Enraged, Chucky attempts to strangle Andy, but Andy uses Tyler's knife to cut off Chucky's hand, dropping him into a giant fan which slices him to pieces. Afterwards, Andy is taken away by the police for questioning, while Kristen is rushed to the nearby hospital.

Question: Who kills the guard
Answer: Chucky