DENVER (CBS4) – A man is dead after allegedly fighting with police officers at the Denver Zoo on Monday. Now Denver police are investigating whether the officers responded appropriately.

Officers said the man attacked and even bit an officer and zoo employee, and violently resisted arrest.

Officers said they tased the man using a stun gun that doesn’t cause a shock to the whole body, but rather pain only to the area where it is placed. After the man was tased police said he began having convulsions and stopped breathing. CPR was performed, but the man died.

As police sort through the bizarre chain of events leading up to the man’s death a woman who says she is his girlfriend and saw everything claims he was suffering from heat stroke. She told a local radio station her boyfriend was putting his head in a fountain to cool off when security showed up.

“That’s when he was like, ‘Okay, hit me, hit me, you want to fight?’ And that’s when I screamed to him, ‘Babe, you’ve got to stop if you love me, you have to stop right now,'” said the victim’s girlfriend, whose first name is Elena.

But it would escalate. Denver police say the man attacked and bit a zoo employee and when officers tried to arrest him he turned on them.

“This is a situation where you’ve got an individual who you can’t get to comply,” Sonny Jackson with Denver police said. “You can’t just let him walk off for fear he might injure somebody else. So you have to take whatever actions you can to stop the situation.”

“They were trying to grab him but he was so aggressive. There was like five zoo keeper securities and seven cops on top of him,” Elena said. “I didn’t see from behind but there was tasers going, snapping all around and I was just freaked out. That’s when he was like, ‘Baby, I’m dying, help me.’ And I couldn’t help him.”

Elena admitted he resisted arrest and even tried to grab an officer’s stun gun. But she insisted officers overreacted as well.

“We feel for the family, we’re very conscientious of that,” Jackson said. “We also feel for the officers, they don’t feel good about what happened last night; no one does.”

While Elena said her boyfriend wasn’t on drugs, police said they did find drugs and drug paraphernalia on him.

The family met with the chief of staff for Mayor Michael Hancock on Tuesday wanting more information. But until an autopsy comes back, the cause of death isn’t known.

Three Denver police officers and one zoo employee suffered injuries in the incident that required treatment at a hospital.