The Maywood, Illinois, Police Department is investigating Myrtle Brown's death as a homicide. The 73-year-old woman was the mother of Sergio Brown, a former NFL player, who is missing, according to authorities and his relatives.

It was the family of both who alerted the police. According to local media WGN9, relatives became concerned when both Sergio and his mother did not respond to messages and phone calls. They alerted the authorities, who opened an investigation.

Soon after, Maywood police officers found Myrtle Brown with no signs of life in a creek near her home. Cook County coroner's authorities pronounced Myrtle Brown dead Saturday after conducting an autopsy. According to the county coroner, Brown's death is due to a series of injuries that authorities link to an assault.

The WGN9 network was told by Sheila Simmons, sister of Myrtle Brown, who in the early hours of Saturday was alerted by the authorities and accompanied them in the search around Brown's home. Simmons explained that if at first they did not find the body of his sister, however, the next morning they located her in the creek behind her home.

According to authorities, the whereabouts of Myrtle's son, Sergio Brown, are still unknown. The 35-year-old retired football player played primarily at the safety position for 94 games over seven different seasons. During his career, he played for the New England Patriots, Idianapolis Colts, Jacksonville Jaguars, Atlanta Falcons and Buffalo Bills.

In a message picked up by the Chicago Tribunes, his brother Nick Brown asked Sergio to return home.

Police asked anyone with information about his location to contact authorities at 708-368-4131 or the Maywood Police Department's anonymous tip line at 708-450-1787.