Why did Cullen Mutrie shoot five police officers?

Law enforcement officers raided Cullen Mutrie’s house for a steroid investigation. This ma shot five police officers at his home. One of them, the Greenland Police Chief Michael Maloney,  was killed; 4 police officials were seriously injured. The next morning Cullen Mutrie and a woman were found dead.
It is suspected that Mutrie was applying steroids at the time of the shootout. Jane Young, the New Hampshire Associate Attorney General, claimed that toxicology reports were waiting in order to learn whether metabolites of steroids were in the body of this man.
Police officers reported that Cullen Mutrie had had very muscular appearance. This man worked at Genetix Fitness in Seabrook. It was claimed that he was 6 feet 3 inches tall. He weighed 275 pounds. During a raid that was in July 2010 law enforcement officials discovered anabolic steroids at his home. The policeman Wayne Young found them in a coffee table. He said that he had saw a plastic bag with certain vials. A vial was with powder; others contained liquid. According to the labels, they were steroids.
The New Hampshire State Crime Lab analyzed the vials. It was affirmed that the vials contained such medications, as Trenbolone Acetate, Sustanon 250, Boldenone Undecylenate and Nandrolone Decanoate.
John Miller, a professor of kinesiology, was asked whether a connection between the deadly actions and aggressiveness due to anabolic steroids could present. The professor said that it was plausible. But according to him, it is impossible to conclude that there was a direct link between administration of anabolic steroids and the crime.
John Miller supposed that steroids which were on the black market were provided from legitimate pharmaceutical companies. But he has been mistaken because the majority of steroids that are offered for sales on the black market are manufactured in underground labs. It is even suggested that Cullen Mutrie manufactured steroids.
Since a link between crimes and administration of steroids is a controversial issue, not only police officers but also media investigates the case connected with this killer.