The family of an elderly man who went missing from a park and was found dead is calling for a criminal investigation into the assisted-living facility caring for him. (WUSA9)

The family of a man who was found dead almost a month after he disappeared from a senior citizens picnic in Prince George’s County has called for an investigation into the assisted-living facility they say was caring for him at the time.

Lubin Phipps, 80, vanished Sept. 18 at Watkins Regional Park in Upper Marlboro while on an outing with residents of Woodmore House Assisted Living, say police and family. After weeks of searching, authorities said they found Phipps’s body Sunday in a secluded section of the park.

Now police are investigating Phipps’s death as his family makes funeral arrangements for the Virgin Islands native who suffered from dementia.

“It’s very heartbreaking,” his daughter Michelle Phipps said Monday.

It was unclear how long Phipps had been dead before his body was found and why he hadn’t been discovered during initial searches of the park, said Edward Leyden, an attorney for his family.

Lubin Phipps (Maryland-National Capital Park Police)

The state medical examiner has not yet determined the cause and manner of Phipps’s death, according to the Prince George’s Division of the Maryland-National Capital Park Police, which conducted the initial investigation and search after Phipps’s disappearance. Prince George’s police said the case is currently classified as a death investigation.

If there was wrongdoing, “an accounting and reckoning will and must happen,” Leyden said. “Mr. Phipps walked away and that should not have happened.”

In response to an interview request, We Care Adult Services, the adult day-care center affiliated with Woodmore House, sent a statement expressing sadness and sympathy over Phipps’s death.

“We Care has been supporting seniors and disabled citizens for more than 20 years in Prince George’s County and resolve to work with officials to thoroughly review all of the circumstances surrounding Mr. Phipps’s passing,” the statement said.

Leyden said the family will allow police and prosecutors to conduct investigations into Phipps’s death before considering legal action.

State health authorities have an ongoing investigation at the adult medical day care and at the assisted-living facility, said Christopher Garrett, spokesman for the Maryland Department of Health and Mental Hygiene. Garrett did not say whether the review — which would be done by the Maryland Office of Health Care Quality — resulted directly from Phipps’s disappearance or is connected to a previous concern.

Phipps came to Maryland from the Virgin Islands after his health began to deteriorate, his daughter said.

“We wanted him here with us to enjoy his children and grandchildren,” Michelle Phipps said.

His family eventually moved him into the assisted-living facility in December 2010, where they felt he could get the care and daily companionship he wasn’t getting with a health-care aide coming to their home, Michelle Phipps said.

“We trusted Woodmore House Assisted Living with our father,” she said. “We hoped that they would keep him safe.”

In the past, employees of the facility would call her and inform the family that they would be taking her father on outings, she said. But that didn’t happen last month, when he disappeared, Michelle Phipps said.

On Monday, Phipps’s family remembered him as a fun-loving family man, fond of dancing to Elvis and Ray Charles songs and talking about his days as head chef of a Hilton Hotel in the Virgin Islands.

Relatives are planning a memorial for him in Maryland and in his native St. Thomas, his family said.

“It’s very difficult to deal with,” Michelle Phipps said. “We didn’t expect his last day to be spent out there.”

Jennifer Jenkins contributed to this report.