An East Brunswick man has been arrested in the fatal beating and robbing of a 55-year-old Sayreville woman in her Winding Wood apartment last summer.

Elliot Rivera Jr., 20, who lived an apartment on Main Street, was charged on March 5 with murder, armed robbery and possession of a weapon for an unlawful purpose. Middlesex County Prosecutor Bruce J. Kaplan, Sayreville Police Chief Edward Szkodny and Spotswood Police Chief Karl G. Martin announced the arrest in a joint statement.

Rivera is accused of killing Patricia Cantaloupe in her Sayreville apartment last July.

In a separate case, Rivera was charged in the carjacking of a 57-year-old Monroe woman who was accosted in the parking lot of a ShopRite supermarket in Spotswood in February.

Rivera is being held on $2 million bail in the murder case and an additional $250,000 on the carjacking charge.

An investigation led by Sgt. Thomas Cassidy of the Sayreville Police Department and Investigator Scott Crocco of the Middlesex County Prosecutor’s Office began on July 31 when a building maintenance supervisor found Cantalupe dead in her apartment at the Winding Wood complex off Bordentown Avenue.

An autopsy subsequently showed the woman died from blunt force trauma to the head after she was struck multiple times with a weapon that later was determined to be a hammer, authorities have said.

The suspect, now believed to be Rivera, fled with an undisclosed amount of cash and jewelry, according to the prosecutor’s office.

While county and Sayreville investigators continued to investigate the homicide, police in Spotswood developed Rivera as the suspect in the carjacking. Police there charged him on March 4, and he was arrested after he surrendered at police headquarters on March 5.

The alleged carjacking took place on Feb. 26. Spotswood police were dispatched to the supermarket parking lot after the Monroe woman told authorities she had been approached by a man who grabbed her arm and told her to get into her car, a red Honda. The man fled when the woman screamed.

After Rivera was arrested in the carjacking, police said they developed additional information that led to his being charged in the homicide.

Kaplan praised Spotswood Detective Kevin Palmer and East Brunswick Detective Kevin Zebro, as well as Detective Cassidy and Investigator Crocco for their work on the case. Rivera, who remained in custody earlier this week, was expected to appear for a hearing at the Middlesex County Courthouse in New Brunswick on Monday.