TORONTO -- A middle-aged man who dressed like a high school student and used makeup to look younger is charged with fondling four male teens on city buses. Detectives described the man as a serial stalker who targeted young males riding on crowded buses.

Toronto transit security arrested the man Monday after he was seen rubbing himself against another passenger. At the time, he was wearing makeup and clothing resembling high school attire.

He's accused of rubbing against four young men aged 15 to 20 and investigators suspect there are many others who haven't reported the crime since the sexual assaults began in October. The assaults occurred during morning rush hours, said Det. Lino Murarotto.

Emanuel Mendonca, 51, of Toronto, is charged with four counts of sexual assault.