DETROIT -- Detroit Public School emergency financial manager Robert Bobb said he is very confident someone will be brought to justice within 48 hours in the shooting at a bus stop that injured seven people on Tuesday.

He said the district is tightening security in and around schools across Detroit.

The shooting took place at a bus stop at West Warren and Southfield roads on Detroit’s West side.

Five of the victims were students from Cody Ninth Grade Academy and had just been let out of summer school.

The shooting happened about a block away from the school.

All the victims were transported to local hospitals.

The victim's ages but not identities have been released.

Police said a 14-year-old boy, a 16-year-old boy and a 17-year-old girl are all in critical condition at Sinai Grace Hospital.

A 15-year-old boy and 16-year-old girl are in stable condition.

A 17-year-old boy is in serious and a 17-year-old girl is in temporary serious condition.

Sources said at least three of the teens had to have surgery.

Deputy Detroit Police Chief Rod Liggons said parents who would like more information are being advised to contact the Detroit police at 313-596-2260.

Two gunmen, possibly three, emerged from the green minivan and "asked for a person by name" before they "opened fire at the crowd," said Detroit Public Schools Police Chief Roderick Grimes.

Police said they are investigating whether an incident earlier in the day sparked the shooting but said they believe the gunmen knew some of the people standing at the bus stop.

Witnesses said the men had masks or cloth covering their faces.

"I fell and all I could do was crawl to the brick wall, and when I got up, I heard at least six gunshots," a witness told Local 4.

The girl did not want to be identified because she could possibly be a witness in the case. She also said she saw the gunmen pull up and she yelled at her friends to get down.

Another witness, who asked only to be identified as "P," said she tried to help one of the victims by giving him CPR.

"I was trying to aid him to keep him calm because I didn't want one of the kids who had got shot multiple times to bleed too much," P said.

Police said security cameras at a bank across the street captured the entire shooting on tape.

Investigators will also review security cameras at the gas station and continue to follow up on leads.

Two teens, in handcuffs, were taken into the 12th Precinct Northwestern District Police Department for questioning.

A police source, who didn't want to be named because he wasn't authorized to speak publicly, told Local 4 he believes the teens taken in for questioning were not the shooters.

The police source said they are almost certain the identity of one of the shooters, and they are just looking for him.

Anyone with information is asked to call 1-800 SPEAK UP.