There was no note found. No known volatile encounter just before the event. No ranting and raving to anyone. No drinking binge to which anyone was privy.

In short, Michael Cwiklinski left no bread-crumb trail behind for investigators to follow that could explain what drove him to kill his pregnant wife, Dalia Sabae, and shoot two police officers before turning a gun on himself.

“Why people do these kinds of things? Nobody knows. To get into their heads, I couldn’t tell tell you,” Pennsylvania State Police Cpl. Kiprian Yarosh, the case’s lead investigator, said Tuesday.

“We haven’t uncovered anything, and we have talked to friends, we’ve talked to family, we’ve done searches of where he was living, and there was nothing.”

Even after nearly two weeks of investigation, there is still work to be done, leads to be followed, possible clues to be unearthed.

The state police are awaiting toxicology reports to see if Mr. Cwiklinski had alcohol or drugs in his bloodstream. They are continuing to trace information about the three firearms he used in the attacks — a sawed-off shotgun, a 30.06 rifle and a .35-caliber rifle. Cpl. Yarosh said police believe all three guns belonged to Mr. Cwiklinski and were legal. They have not yet mined any electronic devices for information.

“The computers and stuff were at the scene were his and the victim Dalia’s, so we have those. We haven’t been able to go through those as of yet,” Cpl. Yarosh said. “He may have left something on a computer, a manifesto or something like that.”

Police say Mr. Cwiklinski, 47, killed Canonsburg police Officer Scott Bashioum, 52, and wounded Officer James Saieva when they responded Nov. 10 to a middle-of-the-night domestic dispute call at a duplex on Woodcrest Drive.

Multiple 911 calls had summoned the officers to the apartment Mr. Cwiklinski had shared with Ms. Sabae, 28. But a judge had evicted Mr. Cwiklinski in October after his wife petitioned for a restraining order following a violent incident. The sheriff’s office on Oct. 12 served Mr. Cwiklinski at his place of employment. He had been living in a camper on a friend’s land since then. How and when Mr. Cwiklinski got into the duplex remains unknown; there were no signs of forced entry.

Also unknown, authorities said, is whether Ms. Sabae was killed before or after police arrived. The officers arrived in separate cars at roughly the same time. Officer Bashioum made it out of his vehicle before being shot. He managed to return fire, 15 shots in all, but none struck Mr. Cwiklinski in his second-story window perch, Cpl. Yarosh said. Officer Saieva, who was shot while in his patrol car, did not fire.

“These guys did nothing wrong. They were proceeding to a dangerous situation as they were trained and as they were supposed to. They were ambushed. There was nothing that anybody was going to be able to do,” Cpl. Yarosh said.

After an hours-long standoff, when police finally got inside, they found Ms. Sabae and Mr. Cwiklinski dead. Ballistics analysis would be little help for investigators trying to piece together the sequence of events, so deformed and fragmented were the bullets, Cpl. Yarosh said. Instead, autopsies, the position of the weapons and the location of the bodies led them to determine that Mr. Cwiklinski killed his wife and then himself, and that neither died from bullets fired by police officers.

Cpl. Yarosh said it’s likely that Mr. Cwiklinski planned to try to blow up the scene. While police were rescuing officers Bashioum and Saieva and returning fire, Mr. Cwiklinski shot at his own car, in which he had stowed highly flammable objects. He hit the car twice, but it did not ignite.

“There was an acetylene tank in there, there was a propane tank, a couple of gas cans, a couple of containers of oil. He was a welder. Those types of items were found at his trailer where he was living at and had a little workshop. Now was that an intentional type thing? I don’t know. I believe so because of what was found inside the residence and the way that he was shooting at the vehicle, but I can’t say specifically that he planted that stuff in there that day. He may have been carrying that stuff around there for days,” Cpl. Yarosh said. “I do believe that he had every intention of trying to detonate that vehicle.”

There were also two propane tanks, with valves opened, and a lit acetylene torch just inside the residence.

Investigators have not been in direct contact with Ms. Sabae’s family. She was a native of Egypt and was working in Russia when she first met Mr. Cwiklinski in person after establishing an online relationship. Cpl. Yarosh did not have much more information than that about their contacts or courtship.

“To me it sounds like the perfect controlling situation — somebody from overseas, restricting her. It seems like he controlled her every move, That’s what it appears,” Canonsburg police Chief Alexander Coghill said.

State police have been in touch with the Egyptian consulate in New York, which in turn got in touch with Ms. Sabae’s family.

Police have interviewed Mr. Cwiklinski’s parents and a brother — one of his two siblings. His parents, who have declined interview requests, confirmed for investigators that Mr. Cwiklinski was an Army combat veteran.

Military records showed that he likely served in a combat zone during the first Persian Gulf War, but no details were available. A mental health evaluation obtained by the Pittsburgh Post-Gazette indicated that he had experienced trauma, witnessed killings and had life-threatening encounters.

“We don’t know what happened with him in the war. We don’t know what happened with him in his life,” Cpl. Yarosh said. “They just said he was over there, he did witness some of his platoon get injured, killed.”

Mr. Cwiklinski’s family told investigators that they treated Ms. Sabae well and were fond of her.

“They were as shook up as anybody. They were very remorseful, apologetic. They never saw this coming. They never thought their son would do something like that. The family was very likable towards Dalia. They took her different places. They were helping her get acclimated to the American way, taking her to appointments. They seemed to like her. They were excited about having a grandchild. It’s devastating,” Cpl. Yarosh said.

Although Mr. Cwiklinski’s family confirmed to police that he was known to have had weapons since he was young, it is unclear whether his wife was aware of that. In her petition for a restraining order she did not indicate that he had any guns.

While Mr. Cwiklinski’s family and Ms. Sabae’s friends in Canonsburg recover from the traumatic events, the Canonsburg Police Department is also trying to move forward. Chief Coghill said that while Officer Saieva is doing well physically — he was able to attend Officer Bashioum’s funeral — the chief could not speak to his mental and emotional recovery.

“Really we’re just getting our heads above water,” Chief Coghill said.

In seeking clues to Mr. Cwiklinski’s mindset, in trying to go back and review his finals days of life, investigators have come up empty-handed.

“He didn’t talk to anybody. He didn’t say anything to anybody about that. He didn’t mention anything to anybody about going off the deep end. Are there red flags? In times of anger or times of depression you could look at anybody and say they could be on the brink of breakdown,” Cpl. Yarosh said.

“Everybody wants answers, and sometimes there are no answers.”

Jonathan D. Silver: jsilver@post-gazette.com, 412-263-1962 or on Twitter @jsilverpg.

First Published: November 23, 2016, 5:00 a.m.