The car bombing outside a California fertility clinic that killed one person and injured four others appears to have been driven by anti-natalist ideology, according to two senior law enforcement officials briefed on the incident.

A 25-year-old man believed to be responsible for an explosion that ripped through a Palm Springs, California, fertility clinic left behind “anti-pro-life” writings before carrying out the attack.

Get all the news you need in your inbox each morning. Mills said the identity of the person of interest would not be released immediately to preserve the integrity of the investigation.