Multiple people opened fire Saturday night in a bustling area of Birmingham, Alabama, killing four people and injuring 17 others. Police had not made any arrests as of Sunday evening.

Officials have announced up to $100,000 in reward funds for information leading to the arrest of the gunman or gunmen behind a mass shooting in Birmingham, Alabama.

Some of the four people killed in a deadly Alabama shooting had "extensive criminal" histories and might have been killed in a "cowardly" murder-for-hire hit, authorities said Monday.