MADISON, Wis. (AP) — April Oles-Magdzas was due to give birth to her second daughter Wednesday, a little more than a year after she and her Iraq war veteran husband became new parents.

But when Oles-Magdzas’ mother showed up that day at the couple’s home in Superior, she found the entire family dead of an apparent murder-suicide.

Superior police said Thursday that Matthew Magdzas, a 23-year-old Wisconsin National Guard soldier who earned a combat badge in the Iraq war, shot and killed his pregnant wife, their 13-month-old daughter Lila, and their three dogs before turning the gun on himself.

Investigators believe the killings occurred Tuesday afternoon, but like friends of the couple, they are still wondering why.

Police Capt. Chad La Lor told The Associated Press that Magdzas did not leave behind a suicide note, and that investigators have found no evidence the couple had money problems or was unduly stressed by the pending birth of their daughter. There was no indication either had been unfaithful.

La Lor said investigators plan to subpoena Magdzas’ military medical records to see if he had complained of or been treated for signs of post traumatic stress disorder.

Lt. Col. Jackie Guthrie, a spokeswoman for the Wisconsin National Guard, said the military can not disclose Magdzas’ health records to the public.

A man who answered the phone Thursday and identified himself as the son of Gene Oles said the family had no comment. A Susan Oles and April J. Oles are also listed as in the household.

According to Oles-Magdzas’ friend and former colleague, 36-year-old Tessa Buscko, of Duluth, Minn., Oles-Magdzas was due to give birth by C-section on the day her body was found. She said she didn’t know what could have driven Magdzas to wipe out his family.

‘‘He must have had a flashback or something. I don’t know. That’s crazy. Matt doesn’t seem like that type of person,’’ Buscko said.

‘‘The only thing people can think of is coming back from the war and trying to live a normal life.’’

Magdzas enlisted in the National Guard during the summer of 2004, between his junior and senior years in high school, Guthrie said. He had completed his training by October 2005 and was assigned to the Superior-based 950th Engineer Company.

He volunteered to deploy overseas with the Milwaukee-based 1st Battalion, 121st Field Artillery Regiment in 2006. The unit was tasked with protecting convoys moving from Kuwait into northern Iraq, Guthrie said.

He served as a vehicle gunner and was involved in a small-arms battle in Iraq in November 2006, she said. She did not know exactly where the battle took place. Magdzas received a combat action badge, an award that recognizes participation in combat. His deployment ended in 2007.

Some time after returning to Wisconsin, Magdzas went to work as a firearms instructor for Better Defense, a shooting school that provides classes in northern Wisconsin and southern Minnesota. According to his profile on the school’s website, Magdzas began shooting before he was 12 years old. It also said he received the Purple Heart, an award given to U.S. military personnel wounded or killed in battle. Guthrie said there is no record he received the honor.

The school’s chief executive officer and master instructor, Gary Bjergo, did not immediately respond to phone messages Thursday seeking comment.

Oles-Magdzas attended Carlton High School in Carlton, Minn. Her science teacher, Deb Saunders, described her as an artistic, ‘‘sparkly’’ young lady who was into dancing and cheer leading. She often stopped sad-looking students in the halls to ask them what was wrong, Saunders said.

Buscko said she worked with Oles-Magdzas, and briefly with Magdzas, at Community Connections, a Duluth foster care facility for people with brain injuries. Oles-Magdzas had recently left the home, however, to take a job as an assistant cheer-leading coach this fall at Duluth East High School.

‘‘April’s passion for working with young people was evident to everyone that came into contact with her,’’ the school’s activities director, Shawn Roed, said in a statement. ‘‘She will be sadly missed and our thoughts and prayers go out to her family and friends.’’

Investigators recovered a 9-millimeter handgun in the house they believe Magdzas used. They also discovered what appeared to be a bomb in a backpack in the house, but explosives experts later determined it likely wasn’t and destroyed it.