ST. LOUIS (AP) — St. Louis Mayor Lyda Krewson says the city suffering a rash of child deaths by gunfire this summer will offer a reward of up to $100,000 for information leading to the arrest of those responsible for the killing of four children.

At a news conference Saturday, Krewson said the city hopes the reward until Sept. 1 of $25,000 for each of four unsolved cases will encourage tips from the public. City officials have expressed frustration at the lack of cooperation in several cases, in part because of fears of retaliation from gangs and drug dealers.

At least a dozen children have been killed by gunfire in St. Louis since June . The latest was 8-year-old Jurnee Thompson , who died when fights broke out at a high school football exhibition Friday and shooting started.