A 20-year-old man fatally shot in the lobby of an east-end apartment building early Sunday morning was probably just trying to get some unwelcome party guests to leave when one of them opened fire on him, police say.

Gaethan Kitadi was celebrating his birthday at a friend’s apartment on Main Street near Kingston Road when he and several other friends escorted two unknown men out of the building at around 12:30 a.m.

According to police, surveillance camera footage shows Kitadi and his friends engaged in some sort of conflict with the men in the vestibule of the building. Police say the footage then shows one of the men firing a single shot at Kitadi as he turned his back to the group to head back into the building.

Kitadi, who lived in the building with his siblings and his parents, was pronounced dead a short time later.

A woman who was related to Kitadi was taken to hospital for assessment after exhibiting signs of shock.

“Mr. Kitadi clearly didn’t lead a lifestyle that would lead him into this,” Det. Sgt. Justin VanderHeyden told reporters Sunday. “I think he took it upon himself to be responsible and he stepped in to encourage these people to leave and not come back and it was at that point that he was shot.”

VanderHeyden said about 20 to 30 people were attending the party, which was by invite only.

A handful of those people have been interviewed, however the majority left without speaking to police.

“The uniformed officers who arrived there said it was absolute pandemonium. The lobby was full of people in the early stages of grieving who just couldn’t believe what had happened and I don’t blame people for going home, but now is the time to step up,” VanderHeyden said. “Somebody in that group knew them (the persons of interest) and I am not placing blame on the people that let them in but those people do have a very important piece of the puzzle that I need.”

The first person of interest is described as a black male in his late teens to early 20s. He was last seen wearing a white hooded sweatshirt, dark pants and a black baseball hat.

The second person of interest is also described as a black male in his late teens to early 20s. He was last seen wearing a puffy black jacket with a blue hoody underneath it and white shoes with black accents.

Police say they will only release surveillance camera footage of the persons of interests as a last resort, as innocent parties were also captured on the tape.

Remember for instant breaking news follow @cp24 on Twitter.