Jurors in Newark deliberated for less than a day before convicting Roberto Grillo, 40, on Wednesday of aggravated sexual assault, sexual assault and child endangerment, Acting Essex County Prosecutor Theodore N. Stephens II said.
The sexual assaults occurred in various locations, including the Belleville McDonald's parking lot, prosecutors told the jury.
Grillo tried to kill himself after fleeing to Florida, then was returned to New Jersey, authorities said.
"The victim suffered years of torment at the hands of this defendant," said Assistant Essex County Prosecutor Michael Morris, who handled the case for the state. "She has found justice today."
Grillo has remained at Trenton State Prison after he was convicted of the December 2015 cold-blooded murder of 35-year-old mother of two Yolanda Vega in Rahway.
He faces up to 105 years in jail at sentencing, which Superior Court Martin G. Cronin scheduled for March 27.
Click here to follow Daily Voice Paramus and receive free news updates.