The body of a 4-year-old autistic boy who disappeared in South Boston Sunday was found Monday afternoon, according to Massachusetts State Police.
State police said in a tweet that Mohamed Fofana was found dead on the shoreline of Castle Island, where a relative lost sight of him about 7 p.m. Sunday.
Castle Island is on the northern tip of a stretch of Boston beaches overlooking Boston Harbor.
“With much sadness we report that we located Mohamed’s body at 12:29 PM today on the shoreline of Castle Island. Our detective unit for Suffolk county will conduct the follow up death investigation. We express our deepest condolences to his family,” state police said.
State police announced the search for Fofana on Sunday night on Twitter.
“No potential reasons” for the boy’s disappearance “have been ruled out at this time,” state police said.
Marine units and dive teams from several law enforcement and public safety agencies on Monday searched the section of ocean known as the Western Way, which connects Dorchester Bay to the south and the Boston Main Channel to the north, state police said.
Side-scan sonar was deployed off three boats, providing a sonar image of the ocean bottom. Divers were investigating any anomalies detected by the side-scan sonar, state police said.
They also conducted what amounts to an underwater search along the entire length of the Castle Island sea wall out to a distance of 150 yards off-shore, state police said.
State police’s Air Wing and the U.S. Coast Guard did aerial searches along the coastline, which was also searched by a drone with the Boston Fire Department, state police said.
Detectives reviewed camera footage with the goal of determining Mohamed’s potential route of movement from the playground area, police said.
Sunday’s search, police said, included its marine unit, a dive team and an air wing. Boston police, fire, and emergency medical services along with the Massachusetts Environmental Police, also assisted, state police said.

Fofana was playing at a park on the coastline Sunday at about 7 p.m., state police said. An adult family member was with the boy when the relative lost sight of him.
That relative called 911 and reported the boy missing about 7:30 p.m., state police said.
Troopers from the State Police Detective Unit for Suffolk County also responded, state police said.
NBC Boston reported that the child’s mother said that he was with his grandfather and sister when he disappeared. She also said that he has autism and doesn’t speak. The boy has a tendency to wander off, the news station reported.
“Yesterday they come with grandpa for the playground,” the child’s mother, Mantenjay told NBC Boston. “He called me, ‘I see your daughter but I’m not seeing Mohamed.’ That’s why I come here yesterday. I not see him … I need to find Mohamed because Mohamed don’t do nothing for himself, nothing.”