Chicago ? Three suspects have been arrested in a bank robbery that exploded into gunfire and left a teller dead and two people seriously wounded, federal officials announced Friday.

The FBI has been investigating since the gunmen burst into the Illinois Service Federal Savings and Loan on May 22, got into a gunfight with a guard and fled by car with what authorities called a small amount of cash.

FBI spokesman Ross Rice said the three suspected bank robbers were in FBI custody but did not release their names. One man was arrested earlier this week, the second was arrested early Friday and the third arrest came Friday night, according to Ross and a release from the FBI’s Chicago office.

All three men were expected to be charged with felony armed bank robbery, which carries a sentence of up to 25 years in prison, Ross said.

The bank teller, 23-year-old Tramaine Gibson, was struck in the back and killed in the exchange of fire. A female customer and a male security guard also were wounded.