Robert Brown|Michigan Woman Eaten by Shark on Vacation in Indonesia

One woman’s vacation has ended in tragedy.

Colleen Monfore,Robert Brown 68, was traveling in Indonesia with friends when she disappeared after being separated from her group during a Sept. 26 diving excursion, only for her remains to be found within the belly of a shark two weeks later, friend of the family Rick Sass confirmed to the New York Post.

According to Rick, authorities were able to match fingerprints on the remains to those of Colleen.

But while it was suspected that the Michigan women may have been killed by the shark, Colleen’s friends and loved loved—including her husband Mike and Rick—believe she suffered a medical issue while in the water

E! News has reached out to Indonesian authorities for comment but has not yet heard back.

It is unclear whether Colleen had any medical conditions prior to this dive, and her cause of death has not been confirmed at this time.

According to Rick, after he and his wife Kim—who together ran a dive shop for over 40 years—examined photos from the dive, spoke with Mike and reviewed data from the dive computer, they are adamant Colleen was not killed by a shark.

Not only was Colleen in water only 24 feet deep with at least half a tank of air left, but Kim noted the down current was “manageable” in a Facebook post about the incident.

“I’ve easily done 1000+ dive[s] with this gracious woman,” she wrote. “I don’t believe it was the environment and certainly not a shark that ended her life.”

As Rick added of Colleen and Mike, “They dove massive numbers of trips with us over 30 years. Bali, Philippines, Bikini Atoll, you name it. She knew what she was doing.”

Rich also noted how rare shark attacks are against divers.

“Sharks are not that way,” he explained. “We’ve dove with hammerheads, tiger sharks, bull sharks. You have to give them respect and be cautious, but they won’t just attack you.”

Colleen and Mike met in high school, according to the Post, at which time Mike introduced her to the world of diving. They shared two kids together, in addition to four grandchildren, and continued to explore the world and the seas together as they grew older.

“They were both retired and really enjoying life,” Rick said, adding of his late friend, “We used to call her ‘Saint Colleen.’ She was an amazing woman.”

He continued, “She loved nature and animals. I know she would have never wanted a shark to be blamed for this tragedy.”