Authorities say Alberto Sidonio was killed while trying to protect his younger sister during an exchange involving her 2-year-old daughter.
HOUSTON — A disagreement over a car seat preceded a shooting that killed a young mother and her older brother during an exchange involving a 2-year-old child, according to the Harris County Sheriff’s Office.
Investigators allege that 19-year-old Angel Javier Rodriguez arrived Sunday at a trailer park on West Canino Road to pick up the daughter he shared with Karen Rivera. Rivera questioned why he did not have a car seat, authorities said. The dispute escalated, and Rodriguez is accused of shooting Rivera and her brother, Alberto Sidonio.
Deputies responding at about 11 a.m. found the siblings lying in a driveway in the 200 block of West Canino Road. Both had been shot several times and were pronounced dead despite efforts by relatives to help them before emergency crews arrived, the Sheriff’s Office said.
The couple’s daughter was nearby but was not physically injured. Authorities said a family member took custody of the child after the shooting. Officials have not released additional information about where she was during each part of the confrontation or who is caring for her.
Rodriguez fled after the gunfire, investigators said. Deputies later located him near Will Clayton Parkway in Humble and arrested him. He was booked into the Harris County Jail and charged with capital murder.
The charge means prosecutors allege that Rodriguez committed more than one murder during the same criminal episode. It does not establish guilt. Rodriguez is entitled to challenge the accusation in court, and prosecutors must prove the charge beyond a reasonable doubt.
Authorities said Rivera and Rodriguez had previously been in a relationship. Rodriguez arrived at the home as part of an expected exchange involving their daughter, according to investigators. Police have not said whether the parents had a formal custody order or whether another relative was supposed to supervise the exchange.
The argument began after Rivera noticed that Rodriguez did not have a child safety seat, the Sheriff’s Office said. Investigators allege that Rodriguez then produced a firearm and shot her. No evidence released publicly indicates that Rivera or Sidonio was armed.
Sidonio came outside when he heard the confrontation and tried to intervene, authorities said. Sheriff Ed Gonzalez said the 29-year-old moved in front of his sister in an attempt to shield her. Rodriguez is accused of shooting Sidonio before driving away.
Initial law enforcement statements described Rivera as 17, while later information identified her as 18. The Sheriff’s Office had not publicly clarified the difference as of Tuesday. Family members described her as a young mother devoted to her daughter.
A relative also told KHOU-TV that Rivera had previously sought protection from Rodriguez. Reports did not establish whether a judge granted an order, whether Rodriguez was served with one or whether any restrictions were in force Sunday. Investigators have not publicly detailed previous calls or court proceedings involving the pair.
Gonzalez described the killings as another example of how domestic conflict can quickly become deadly. Detectives continued interviewing witnesses and gathering evidence from the residence, the driveway and the vehicle associated with Rodriguez’s departure.
Rodriguez was scheduled to make his first court appearance Wednesday at the Harris County Criminal Justice Center. The investigation remained open, and authorities asked anyone with direct information about the shooting to contact the Sheriff’s Office.
Author note: Last updated July 28, 2026.