Flowers and signs sit at a memorial across the street from the Chabad of Poway synagogue. Picture: Denis Poroy/AP

San Diego - The 19-year-old man accused of opening fire in a Poway synagogue has been charged with murder and three counts of attempted murder - all with hate crime allegations - as well as arson for a fire at an Escondido mosque earlier this year.

According to the district attorney's office, John T. Earnest has been charged with one count of murder with a hate-crime special circumstance and gun allegations, three counts of attempted murder with hate-crime and gun allegations and arson of a house of worship.

Earnest will be arraigned Tuesday in San Diego Superior Court. He will be represented by the public defender's office, and attorneys there met briefly with him Monday morning.

Late Saturday morning, a gunman opened fire at the Chabad of Poway, killing a 60-year-old woman and injuring three others, including an 8-year-old girl, before fleeing.

Authorities arrested Earnest moments later.

Earnest is also charged with arson in an early morning fire at an Escondido mosque last month. About 3:15 a.m. on March 24, someone set a fire outside the Dar-ul-Arqam Mosque on Sixth Street near South Escondido Boulevard.

One of the seven people inside the building spotted the flames, and the group doused the fire. Authorities said the fire had been set intentionally, and that the arsonist used accelerant.

In the driveway of the mosque, investigators found vandalism referencing the March 15 shootings at two New Zealand mosques that left 50 people dead.