Almost four months after a gang-related shooting left two dead and 23 hurt on Danzig Street, Toronto police have laid a pair of murder charges in what has been described as the city's worst mass shooting.

Two counts of first-degree murder were laid against Shaquan Mesquito, 18, also known as Bam Bam.

Mesquito also faces 23 counts of aggravated assault for wounding more than 20 people at the crowded outdoor party in Scarborough where the shooting took place on July 16.

"This was an attack on the security and safety of the entire Danzig Street community," said Toronto police Staff Insp. Greg McLane.

Toronto police released a composite sketch of two men they want to speak with in connection to the Danzig Street shooting, which killed two people and injured 23 others.Toronto police released a composite sketch of two men they want to speak with in connection to the Danzig Street shooting, which killed two people and injured 23 others. (Toronto Police)

Mesquito is also charged with the attempted murder of Nahom Tsegazab, a 19-year-old Toronto resident who was at the party and who was charged on July 19 with reckless discharge of a firearm.

McLane said police believe the shooting began after one member of a gang known as the Malvern Crew was denied access to the barbeque attended by more than 100 people. McLane said a rival gang, the Galloway Boys, had taken ownership of the gathering. Police believe the person who was denied access to the party called fellow gang members after being turned away and returned to the party.

"This resulted in a violent confrontation that involved a number of firearms," said McLane.

The shooting shocked the city and claimed the lives of Shyanne Charles, 14, and 23-year-old Joshua Yasay. Police say both were innocent victims caught in the crossfire and not part of the dispute that caused the shooting.

Mesquito has been in jail since shortly after the shooting, facing a charge of threatening to cause serious bodily harm also related to the barbecue. He appeared in court Wednesday on the new charges and was remanded into custody.

Police also released composite drawings Thursday of two men they want to identify who were at the party. Both are young black men in their 20s. One has a prominent scar under his left eye.

McLane said it's not yet known if they were involved or were just witnesses, but police would like to speak with them.

Police are also seeking information from anyone who was at the Danzig Street party.

"This investigation is far from over," said McLane.