LENEXA, Kan. — Crime scene technicians found pipe bombs and a GPS tracking device in a car parked outside the scene of a double murder-suicide in Lenexa, according to an affidavit/search warrant application in the case.

They also found a “ghost gun” and other weapons inside the home, according to court documents FOX4 obtained Wednesday.

Investigators said 20-year-old John M. Williamson of Lenexa, Kansas; and 22-year-old Sara M. Beck and 37-year-old Dustin J. Johnson of Belton died in the shooting early Sunday morning.

Police believe Johnson shot and killed Beck, his ex-girlfriend, and Williamson, who “had been seeing each other.” Johnson then died by suicide.

According to newly released court documents, Johnson was found wearing a tactical vest and had an empty holster on his belt. He also had an additional holster that contained a silver revolver in his boot.

Detectives also found a black assault rifle near Johnson. The affidavit states the weapon was made using various parts and manufactured into a complete assault weapon. There were no serial numbers located on the firearm.

“They found explosives. They found ghost guns, which means he was in the process of making these weapons. Whether it’s to avoid being detected or lack of traceability, certainly showed some of the fabrics of intent,” former FBI Special Agent in Charge Michael Tabman told FOX4.

“There’s good reason to believe if he brought explosives to the scene, there’s more back at home or he’s making them, so they did have an urgent need and secure those before there was an accident.”

A car registered to Johnson was found in the driveway outside of the Lenexa home. It was towed to the Johnson County Crime Lab to be processed.

The lab notified detectives Monday that they found a GPS tracking device on the exterior of the car and four pipe bombs inside it, according to court papers.

The Olathe Fire Department reported the devices seemed to be an improvised delayed grenade. The Olathe Bomb Unit said the explosives were not made at the crime scene.

Detectives used that information to apply for a warrant to search the duplex in Belton where Johnson lived Tuesday afternoon.

The affidavit shows officers were looking for evidence of explosives or that an explosive device was made at the duplex. They also searched for a variety of guns and weapons, or evidence of them.

Belton police told FOX4 the explosive devices were taken to rural location and destroyed in controlled detonation.

Lenexa police said they believe Johnson was using the tracking device they found in his car to keep tabs on his ex-girlfriend. Detectives are still investigating why the tracker was found in his car.

“Unfortunately, I’ve seen this many times in my career: If I can’t have you, nobody can,” Tabman said. “And we know this love murder, where just can’t handle not having that relationship, them seeing someone else. This is how it ends.

“It’s scary that something like this can happen. (We) have to be aware we live in a dangerous world.”

Through court records, FOX4 also learned Johnson previously served time in the Kansas Department of Corrections 12 years ago. Documents state Johnson served less than a year between 2009 and 2010 for attempted felony theft.