Two New Mexico children helped save their mom when they handed a note to their school bus driver warning that their mom was in danger — leading to the arrest of her boyfriend for alleged abuse, cops said.

The Las Crucesmother secretly wrote the note and asked two of her kids to give it to their bus driver after her boyfriend confiscated her phone and prevented her from seeking help, police said Tuesday.

“The children did as they were asked, and the attentive bus driver called 911 to summon police to the home,” authorities said.

Police said they discovered the mother “with multiple cuts, bruises and abrasions.”

The injuries were consistent with her claims that her boyfriend, who was identified as 40-year-old Erik Alvarado, attacked her Thursday night, police said.

Alvarado allegedly battered the woman, strangled her, and tried to suffocate her twice with a pillow and a shirt, police said.

The woman told authorities that Alvarado also threatened to kill her.

The couple share three children, who witnessed much of the abuse, police said.

Police tracked down Alvarado on Friday night and arrested him on charges of aggravated battery against a household member and deprivation of property.

He was being held Tuesday night in the Dona Ana County Detention Center without bond, authorities said.