CHICAGO (CBS)–A week has passed since police released chilling surveillance video of a masked killer walking calmly down a sidewalk in broad daylight after randomly gunning down a man walking his dog on a Sunday morning.

The killer, who has not been caught, continued the murderous spree that has put the Rogers Park neighborhood on high alert by killing 24-year-old Eliyahu Moscowitz a few days later as he walked in Loyola Park.

As police work to solve the killings of Moscowitz and 67-year-old Douglass Watts, rumors have circulated about how many detectives have been working on the case, with many media reports saying more than three dozen detectives were assigned to help catch the Rogers Park killer.

Some critics have questioned whether police are allocating more resources than usual to the North Side killings–where murders are much less common than in Chicago’s violence-prone South and West sides.

Chicago police superintendent Eddie Johnson addressed the criticism, saying it would be unusual to assign such a high volume of detectives to work on a pair of cases in one neighborhood.

“That is a huge, huge volume of detectives,” Johnson said at a recent community meeting. “There’s been a number of incidents up there where there’s 40 or more detectives working, but there are not 40 detectives assigned to just that one case.”

“We have promising leads,” Johnson said. “I’m proud of the work (detectives) are doing so far.”

Johnson declined to provide details on those leads, however.

“We’ll just keep investigating and hopefully we’ll bring this guy in,” Johnson said.