The death of a Kalihi grandmother last weekend has baffled Honolulu homicide investigators.

Fernanda Tuvera, 79, was strangled and smothered, according to an autopsy by the Honolulu medical examiner.

But there were no signs of forced entry into her home and both doors to her place were still locked Saturday afternoon when relatives arrived and found Tuvera, said Lt. Bill Kato, head of the Honolulu Police Department's homicide detail.

Her home was "tidy" and did not look as if it had been searched or anything was stolen, Kato said. "The circumstances here make us feel very uncomfortable," he said.

Tuvera was last seen alive about 8 p.m. Friday by her caretaker, Kato said. She was found by relatives about 2 p.m. Saturday when they went to check on her because they hadn't heard from her in the morning. She was found "lying on the floor next to her sewing machine," Kato said.

Police have no "obvious suspects" and are asking the public's help to solve the case. Anyone who saw something suspicious at Tuvera's home at 2365 Haumana Place is asked to call police.

Detectives canvassed the neighborhood at the end of a cul-de-sac on Monday night, but had trouble getting the area's many elderly residents to come to the door, Kato said.

They returned Tuesday during the day.

No one saw or heard anything unusual, but they also keep to themselves, he said. "A lot of them were telling us that when it gets dark, they won't come out."

Kato urged residents not to open their doors to any stranger and if the person won't leave, to call police.

Reach Mike Gordon at mgordon@honoluluadvertiser.com.