Former Boston developer Frank McCourt, who turned a $1.278 billion profit on the sale of the Los Angeles Dodgers, has given a tiny portion of those proceeds to the Watertown Police Foundation. McCourt, who grew up in Watertown, donated $25,000, which accounts for about a quarter of the foundation’s current gross revenue. Police Chief Edward Deveau said McCourt called the police station unexpectedly and asked to drop by. “He explained that he [and his siblings] grew up on Russell Avenue here in Watertown,” and although McCourt’s mother lives in New Hampshire now, “she still considers Watertown her hometown,” Deveau said. “When she saw everything play out on TV, she called Frank up and said we as a family should make a donation to ‘my’ police department.” The Watertown Police Foundation was created the week after the Boston Marathon bombings. Suspected bomber Tamerlan Tsarnaev was killed during a shoot-out with police in Watertown and his brother, Dzhokhar Tsarnaev, was captured there after an intense manhunt.