Dawe, 43, killed Julianne Hibbs inside the clinic in the Villa Nova Plaza in Conception Bay South on Tuesday night, shortly before he killed Vince Dillon in the parking lot.
Dawe later drove to the Anglican Cemetery on Kenmount Road in nearby Mount Pearl, where he killed himself.
The Royal Newfoundland Constabulary has labelled it a double murder-suicide.
Marilyn Crotty, who lived near Dawe on Chaytor's Road in a quiet residential area, said her neighbour became a different person after Hibbs, 35, moved out a few years ago.
"I guess he just didn't get over that," Crotty told CBC News.
"It's just been on his mind forever — I know that much."
Neighbour believes guns found in house
Police, who had searched the area of Dawe's house before his body was found Wednesday morning, returned in the afternoon and were seen removing boxes.
While police have not commented on what was removed, a clearly shaken Crotty said she believes they contained guns.
"A lot of boxes — long rifle boxes — and it said evidence on the box and there was a picture of a gun on it, so I guess that's probably what it was," said Crotty, adding that about 20 boxes were removed.
Crotty described Hibbs as a "very nice person" and a "very good neighbour."
The shootings took place near a pizza store where Dawe worked a decade ago. Hibbs was known to accompany Dawe as he delivered pizzas.
Sources told CBC News that Hibbs and Dillon, 45, had been a couple for a number years.
Dillon was a former deejay and bouncer at the Cotton Club, a strip club in downtown St. John's, and Hibbs was a dancer there, performing under the stage name Paris.
Hibbs' Facebook profile also shows that she had been pursuing a modelling career.
'I just can't believe it'
Friends and family have been expressing their grief on her Facebook page.
"I just can't believe it. You were one of the sweetest and strongest women I know. You were a friend to everyone and always had a kind heart," wrote one friend.
Another, describing her as a "beautiful angel," wrote: "Will think about you and Vinny often as will the rest of the people u have touched."
Hibbs's final message on Facebook was last Sunday.
"Happy Thanksgiving everyone," she wrote. "Here's to health, faith, love, family, friends and time to enjoy them."