A grandfather was fatally stabbed in Michigan on Saturday after trying to convince a man to stop using drugs in front of children, police said.

The grandfather was at his grandchild’s first birthday party at Grant Park in Utica when he approached a man on a bench who appeared to be doing drugs and asked him to stop using drugs in front of the children, WXYZ reported.

The suspect then allegedly stabbed the grandfather, who has not been identified, at least 15 times.

Ten police officers and two ambulances arrived at the scene, where officials pronounced the grandfather dead and arrested the alleged attacker, WJBK reported.

Witnesses said the “enraged man” attacked the grandfather in the park in front of family members.

“He was enraged, he seemed like he had the strength of the Tasmanian devil,” Amanda Pasho, who lives across the street from where the attack occurred, told the Macomb Daily. “My heart goes out to the family of that poor man. I can’t believe this happened in front of them.”

Pasho added that she saw the suspect stick a machete-like weapon into the victim’s body, causing the victim’s blood-covered body to fall to the ground.

“He had his arms up to fend off the man from stabbing him. The man put his knee in the guy’s abdomen to hold him down and then put his arm across his face and began stabbing him with a knife, like non-stop, just jabbing at him with the knife,” she said.

Police are still investigating the incident.