A St. Paul man lashed out in a rage against his longtime girlfriend when he found out that her underwear was in their dryer with another man’s clothing, charges say.

Prosecutors charged Jesus Hernandez, 39, with terroristic threats and domestic assault by strangulation in Monday’s alleged attack on the West Side. He beat the woman and threatened one of their three children, a 12-year-old boy, saying that if he kept begging the father to stop, “I’ll kill you, too!” the criminal complaint said.

According to the charges filed Tuesday in Ramsey County District Court:

When police responded to a 7 a.m. 911 call from the home in the 100 block of West Baker Street, they found the “extremely distraught” victim in a torn, blood-smeared T-shirt. The left side of her face was swollen and turning purple.

Her 19-year-old son had called police to report that Hernandez was assaulting his mother and threatening to have people “rape” her.

The incident started about 3:30 a.m. when she put the clothing of a house guest into the washing machine, the woman told police. The other man, identified as M.G., was a friend of Hernandez who was staying with them.

“Hernandez became upset over this,” the complaint said.

An hour later, the 41-year-old woman put the friend’s clothes into the dryer with some of her own.

“Hernandez became enraged that (her) underwear and M.G.’s clothing were in the dryer together,” the charges said. “She said Hernandez had accused her of infidelity in the past.”

He stormed out of the house into the garage, where he had a makeshift bar. He drank “multiple shots” of liquor and became very drunk. When the woman went to check on him about 5:30 a.m., he was sitting in the garage. At this point, he had two BB guns with him and told his girlfriend, “I’m waiting for police.”

Back in the house, Hernandez yelled at the woman and threatened her life. He slapped her down, causing her head to slam into a bedroom door frame.

She said he squeezed her throat, making it hard for her to breath. He also pointed one of the black BB guns at the woman, threatening to kill her.

The assault continued as the couple’s three children looked on, screaming.

Their 12-year-old son told police he kept begging his father to stop. But Hernandez turned to him, saying, “You tell me to stop again and I’ll kill you, too!” Their 14-year-old daughter tried to call 911 on an emergency-only phone, but it was making noises, she said. The girl was afraid her father would hear it, so she hung up.

Hernandez told police he was “pretty pissed off” at his girlfriend because she had talked to another man. When reminded about the laundry, he admitted that made him angry, too. He had had a relapse, gotten drunk and had a “bad day,” he said.

Hernandez was being held Wednesday in Ramsey County District Court.

Emily Gurnon can be reached at 651-228-5522. Follow her at twitter.com/emilygurnon.