The brother of an American college student found dead in the Tiber River says authorities are investigating whether the teen was robbed and killed.

Cole Solomon, Beau Solomon's 23-year-old brother, told the Milwaukee Journal Sentinel on Monday that investigators are treating the incident as a murder.

He says his brother's body was found with a head wound and blood on his shirt. He added that thousands of dollars were charged to Beau Solomon's credit card after his disappearance.

The 19-year-old from Spring Green, Wisconsin, went missing early Friday morning after going out with some friends at a pub shortly after he arrived for an exchange program at John Cabot University in Rome. His body was found Monday.

Solomon had just completed his first year at the University of Wisconsin-Madison.