He is a ruthless Romanian poacher who murdered the titular ape's mother as well as Dr. Ruth Young, mother of the film's protagonist Jill Young. However, in the process, Strasser loses his thumb and trigger finger after Joe bit him, and he swears revenge on the gorilla for the damage. 12 years later, Strasser sees Joe on TV and decides to pay the ape a little visit and get his revenge on him for costing him his fingers, and he will stop at nothing until he kills him (along with Jill or anyone else who gets in his way).
Andrei Strasser can best be described as ruthless, evil, sadistic, arrogant, remorseless, greedy, conniving and overall cruel in nature with no regard for any life but his own.
Strasser is also very conniving and sly, as he runs a fake animal reserve, while in actuality, he is selling animal organs off the black market. He also manges to completely manipulate Jill into believing he was on her side and tricked her into believing he'd take good care of Joe back in Africa.
Strasser also has no remorse for attempting to kill people as well--best proven when a missed shot intended for Jill causes a deadly fire to spread throughout the carnival, endangering a child trapped on the Ferris wheel. This causes his henchman Garth to turn against him.
All and all, Strasser's powerful grudge against Jill and Joe leads to his downfall, as he is so intent on shooting Jill, that he doesn't notice the giant ape looming behind him until it's too late and Joe gives the wicked poacher his well-deserved and literally shocking demise.
Role in the film
One night, Andrei Strasser is ambushing a herd of gorillas. He shoots baby Joe's mother, as well as primatologist Dr. Ruth Young, mother of Jill Young. Strasser attempts to put to put the baby ape in a sack, but Joe bites off Strasser's thumb and trigger finger, and Strasser swears vengeance for his severed hand as he retreats. Before she dies of her wounds, Ruth tells Jill to promise her to take care of Joe, to which Jill agrees.
12 years later, Strasser is now running a fake animal preserve in Raja while in reality selling animal organs off on the black market. He gets a phone call from with one of his men, Pindi who claims to have seen to believe there is a 2,200 pound gorilla, but Strasser doesn't believe him, stating that Pindi had been drinking too much and slams the phone down.
One day, Strasser discovers that Pindi was right about the giant ape when he sees about Joe and Jill Young on the Television. He and and his henchman Garth recognize the ape as the one who bit Strasser's fingers off. Strasser wants to get revenge on Joe for biting his fingers off. He tells Garth to book them tickets to America and that he has a plan to convince Jill to part with Joe.
At first, Jill fails to recognize Strasser as the poacher who killed both her mother and Joe's, since Strasser hides his right hand in his coat pocket. Strasser, claiming to be an old friend of Ruth's, tries to persuade Jill that Joe would be better off in his wildlife refuge back in Africa.
Later, during a gala, Garth uses a poacher's noisemaker to scare Joe into a frenzy. Joe trashes the gala, recognizes Strasser and tries to attack him. Joe is then tranquilized and placed in a concrete bunker. When Jill learns that Joe may be euthanized, she decides to take Strasser's offer. Strasser uses the truck to get Joe inside with Jill's help.
Meanwhile, the refuge director Gregg O'Hara has realized that Strasser is a poacher (upon seeing the poaching noisemaker the maintenance had found) and goes after both Jill and Joe. On the way to the airport, Jill notices the half-glove covering Strasser's missing fingers, and finally realizes who he really is. Just then, Strasser notices Greg pursuing them and pulls out his revolver, but Jill punches him in the chest, then leaps out of the truck and into the street. Joe sees her and rocks the truck over onto its side and escapes. Greg finds Jill, who reveals to him that Strasser killed her mother and plans to kill Joe and they rush off to find him.
Jill and Greg eventually locate Joe at a carnival where he is playfully wreaking havoc. Strasser arrives at the carnival and aims his gun at Jill. But Garth pushes Strasser's gun away from Jill, causing him to fire at a spotlight, which starts a fire and causes the Ferris wheel to break down. Realizing Strasser's true nature as a murderer, Garth tells Strasser that he quits, but Strasser knocks him out unconscious with his gun before confronting Jill.
Strasser eventually confronts Jill and attempts to shoot her, but Joe manages to sneak up behind them and grabs him, roaring in the evil poacher's face, before flinging him onto some electrical wires over a transformer. Short two fingers on the hand holding the wire, Strasser's grip fails and he falls onto the transformer, electrocuting him to death and leaving only his half-glove hanging from the wiring.