MOUNT VERNON — A Mount Vernon High School teacher was charged Tuesday with attempted murder, assault and burglary in an attack with a baseball bat Sunday that injured his wife and a neighbor who tried to intervene, the county’s top prosecutor said.

Alan T. Gromus, 56, of Anacortes, is charged with attempted first-degree murder involving the attack on his wife, first-degree assault regarding the injury to his neighbor and first-degree burglary because of where the attack on the neighbor took place, Skagit County Prosecutor Rich Weyrich said.

“We allege that he followed the neighbor into (the neighbor’s) living quarters and assaulted him there,” Weyrich said.

Weyrich said no other details about the incident, including possible motive, were available at this time.

Gromus' arraignment hearing in Skagit County Superior Court is scheduled for Thursday.

His 53-year-old wife received head injuries and a broken leg, and his neighbor’s ankle was broken, according to the Skagit County Sheriff’s Department.

The wife was taken to Island Hospital’s emergency room and then airlifted to Harborview Medical Center in Seattle but was later released, Chief Criminal Sheriff’s Deputy Will Reichardt said.

Deputies were called to a Campbell Lake Road residence on Fidalgo Island shortly after 8 p.m. Sunday, and Gromus was arrested without incident, Reichardt said.

He was initially booked into Skagit County Jail Sunday night on suspicion of two counts of assault, and bail was set at $75,000. After charges were filed, bail was set at $500,000. Gromus remained in the county jail Tuesday afternoon.

News of Sunday’s incident sent shock waves through the high school Monday because both Gromus and his wife work for the school district. Gromus teaches career and technical education.

Mount Vernon High School Principal Dave Anderson said the mood on campus was “somber, just aghast” as teachers and students learned of the allegations.

“We have a lot of emotions going through our campus right now,” he said.

Anderson said he called an emergency staff meeting Monday morning and wrote a letter based on information from the Sheriff’s Department that teachers read to students during their second-period class.

“We want to be proactive, and we’re going to get accurate information out without speculation,” he said.

The letter encouraged students and staff to avoid speculation and to allow the legal system to determine the facts. Students were also able to discuss the news in the class after teachers read the letter.

“Staff have reported to me that it went well,” Anderson said. “Students appreciated the information.”

The letter, which Anderson also was sending home to parents, said substitutes would fill both positions.

“When unfortunate circumstances have the potential to disrupt our learning environment, it is at this time we engage in open, honest discussions with each other,” it stated.