They came home to bury mom... and her killer

https://www.imdb.com/title/tt0430105/

Four adopted brothers come to avenge their mother's death at what appears to be a random killing in a grocery store robbery. However, the boy's investigation of the death reveals more nefarious activities involving the one brother's business dealings with a notorious local hoodlum. Two cops, who are trying to solve the case, may also not be what they seem. While a fairly standard tale, their are still several twists and unexpected turns that keeps things interesting.

In Detroit, when the beloved citizen Evelyn Mercer is murdered in a store heist, her four dangerous stepsons come to her funeral. Bobby Mercer, Angel Mercer and Jack Mercer join the regenerated ex-union leader Jeremiah Mercer, and they decide to investigate the murder. They disclose that her execution was intentional, and resolve to find the criminals by themselves.

This movie is about the four mercer brothers Bobby; Angel; Jeremiah and Jack. Their four step brothers raised as real brothers. After they had split apart for a while they are reunited when there adoptive mother is killed in a grocery store shooting. When they go back the brothers take it apon them selves to find out who her killer is, while the gangster brothers become closer to finding who it is; they become closer to each other