A December graduate of Iowa State was one of two people found shot dead Tuesday in a Des Moines suburb, police said Wednesday.

Sarah Dahlke and a 41-year-old Des Moines social worker, Greg Gaul, were discovered inside the Johnston home of a family Dahlke was house-sitting for while they were on a trip to the Cayman Islands. Police said they weren’t sure why Gaul was at the house.

Police notified the owners of the home, Matthew Pirtle and Sarah Collinson, of the double homicide — and of the apparent suicide of Pirtle’s 16-year-old son, Tyler, who is suspected in the killings.

An all-points bulletin for Tyler Pirtle was issued by police after the bodies were discovered. Officials in Mesa County, Colo. said they believed Pirtle had committed suicide in his vehicle near the Utah border.

Dahlke received a degree in marketing and Spanish from Iowa State in December and was engaged to be married to ISU alumnus Jason Dolash, an agricultural engineer who lives in Decatur, Ill.

Laughter, tears

In Ames Wednesday, Sarah Dahlke’s friends gathered together to laugh about shared memories and cry for the loss of their friend.

Crowded in a Frederiksen Court apartment, seven of her friends recalled the moments they shared with her.

The last time they saw Dahlke was Saturday. They signed her up for “For Better or for Worse,” a reality TV show that lets friends and family plan a couple’s wedding.

“We went to McDonald’s, and she wanted Subway when we got there,” said Crystal Gibson, senior in management.

Dahlke’s friends have spent the past two days together reminiscing and supporting each other.

The group spoke about how “warm and fuzzy” Dahlke made them feel, but they could not vocalize easily what Dahlke was like. They struggled with short descriptions for a few moments.

“I just think her whole aura, when you’re just around her — you know what I mean — she made you feel good,” said Molly Schiel, senior in anthropology.

The memories came flooding back after a few moments of silence.

“[The memory I hold closest] is the first time I met everybody, and Sarah was the first one I met, and she just made me feel so welcome,” said Erin Matei, senior in landscape architecture.

As tears began to fall, the friends fell silent again.

“I’ve been her best friend since we were 10,” said Amy Swanson, senior in chemical engineering.

Discussing Dahlke’s personality quirks lightened their mood, causing them to laugh when they remembered when she placed her pajamas on the space heater and almost burned down the building.

“She walks out, and she’s like ‘[gasp], I know what it is,’ and opened the door,” said Elisabeth Peters, senior in liberal studies.

They all laughed at the story and started interjecting, adding more strange quirks to the list.

She ate everything cold and she couldn’t cook. When asked what Dahlke’s passion was, her friends replied with one word.

“Jason.”

Dolash and Dahlke were engaged after he proposed to her on top of the Sears Tower in Chicago.

“That’s all she wanted to do, just graduate and be with Jason,” Swanson said.

Dolash pursued Dahlke fervently after they were introduced. He brought her flowers every day for a week and kept asking her for a date.

“He wouldn’t give up,” said Ryan Husak, graduate student in animal science.

They were set to be married Oct. 2.

The news of her death came as a shock.

“You always hear about it happening,” said Aaron Bullington, senior in biology. “It’s just heart-wrenching to think somebody would have that much hate.”

In the end, one sentence described Dahlke.

“Sarah’s great.”

— The Associated Press contributed to this article.