The police in Illinois were searching for the former N.F.L. player Sergio Brown after his mother was found dead from multiple injuries related to an assault near a creek behind her home on Saturday, the authorities said.
The Brown family alerted the police after being unable to reach either of them, the Maywood Police Department said in a news release.
“Maywood police officers initiated a missing person report and began making attempts to locate both individuals,” the news release said.
Maywood, a village of about 23,000 residents, is about 12 miles west of downtown Chicago.
The body of Myrtle Brown, 73, was discovered near a creek behind her home on Saturday, the police said.
Ms. Brown’s body was taken to the Cook County Medical Examiner’s Office, according to Natalia Derevyanny, a spokeswoman for the office.
Ms. Derevyanny said that Ms. Brown died from multiple injuries because of an assault and that her death had been ruled a homicide.
As of Monday morning, it was unclear if the authorities had gotten closer to finding Mr. Brown or if they had received new leads on his whereabouts.
Carmen Rivera, a public information officer for the Maywood Police Department, said on Monday morning that she did not have any information regarding Mr. Brown beyond the initial news release from Saturday.
Nick Brown, Mr. Brown’s brother, asked for the public’s help on social media on Sunday in finding him.
“My brother Sergio is still missing,” Mr. Brown wrote on Instagram. “If anyone knows where he is I want him to know that I love you and please come home.”
Mr. Brown also said that his mother, Myrtle, always told him that “tough times don’t last.” He added, “Our last conversation about tough times being temporary is my beacon of hope.”
The police had been called to the Brown residence in the past, Carlos Cortez, a neighbor of the family, told WBBM, a local news station.
“Her family came and knocked on the door and was looking for her because they put out a police report because she was missing for 72 hours,” Mr. Cortez told WBBM. “So, we tried to help them as much as possible.”
Mr. Cortez told the authorities that he last saw the Browns on Thursday, according to WBBM, and also handed over video footage from his doorbell camera.
Mr. Brown, 35, played for the University of Notre Dame before joining the New England Patriots as a defensive back in 2010.
He also played for the Indianapolis Colts and the Jacksonville Jaguars and ended his career in the 2016 season with the Buffalo Bills.