Mother, Uncle of 2 Inmates Held in Plot to Kill Witnesses : Crime: Police say Pico Rivera residents wanted revenge on four neighbors whose testimony helped convict teen-agers of murder two years ago.

Two years after a pair of teen-age brothers were sent to prison for murder, their mother and an uncle have been arrested on suspicion of plotting the murder-for-hire of four neighbors whose testimony sent the brothers to prison, authorities said.

Susan Gonzales, 37, and her brother, Thomas Hiromoto, 38, both of Pico Rivera, were arrested by sheriff’s investigators Saturday night after being under surveillance for some time. They were booked on suspicion of solicitation and conspiracy to commit murder, and were held on $500,000 bail.

“They wanted to perform an execution,� Deputy Rich Erickson said.

Hiromoto was also booked on suspicion of selling heroin and possession of a sawed-off shotgun.

Sheriff’s spokesmen described the motive for the murder-for-hire plan as “revenge.� The intended targets were four neighbors whose testimony helped convict two of Susan Gonzales’ sons two years ago. Steven Gonzales, 20, and his brother Andrew, 18, were convicted of murder, Erickson said. Details of the crime were not available late Sunday.

Deputies arrested two other family members on unrelated charges Saturday. Susan Gonzales’ sister, Dale Pallan, 33, was booked on suspicion of conspiracy to distribute heroin. And a 14-year-old was arrested on suspicion of possessing a handgun and stolen property, and was being held in juvenile hall.