SAN FRANCISCO (CBS SF)_ A man found critically injured Sunday in San Francisco’s Duboce Triangle neighborhood may have been the victim of an assault and attempted murder, police said on Tuesday.

New evidence presented to San Francisco police indicate that the man was assaulted before he was found on the ground at about 7:30 a.m. Sunday near the corner of Duboce Avenue and Church Street, San Francisco police spokesman Officer Albie Esparza said.

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The victim was taken to San Francisco General Hospital with critical injuries and had no wallet or ID with him, hospital spokeswoman Rachael Kagan said.

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He remained unidentified until Monday afternoon, when a neighbor recognized him in media reports and contacted his family, who went to the hospital, Kagan said.

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Esparza said police are seeking a suspect in what they are considering an attempted murder and assault with a deadly weapon investigation. The suspect was described only as a white man in his 20s or 30s wearing a gray sweater.