Coco’s been missing for nearly a month.

So the owners of the 5-year-old female Shih Tzu are offering a $2,000 reward.

Coco disappeared between the evening of June 5 and the morning of June 6, according to owner Lionel Lun. The 10-pound pooch was staying with a dog sitter in the Kaimuki neighborhood of Eighth Avenue and Alohea Street.

Lun said he suspects Coco escaped through a pet door. He has since learned that the sitter earlier lost another dog.

"Had I known that she had lost a dog before we would have never used her," Lun said, adding that he plans to file a complaint with the Better Business Bureau.

The next day, Lun and his wife, Naoko, put up fliers saying there was an unspecified reward for their dog. When Naoko Lun didn’t get a response, she added a $1,000 reward to the fliers before eventually increasing it to $2,000 on Monday.

Shih Tzu, weighing between 9 and 16 pounds, can sell for more than $1,000, Naoko Lun said. If someone has Coco, the $2,000 would allow the person to buy another dog or Shih Tzu.

"So (with) $2,000 they can buy another puppy or Shih Tzu but still they can keep some money," she said.

Also noted on the fliers, the couple suspects Coco could be with a homeless person, but not the woman who hangs around the Hale Vietnam restaurant off Wai­alae Avenue.

"We got a lot of calls that this lady has it, but it’s not our dog," Lun said.

With Coco gone, their lives have come to a halt.

"We’re doing what we’re doing, but it’s concentrating on trying to get Coco back, wherever she is," Lun said, adding that Coco is special to his wife and 8-year-old daughter.

The beige and tan dog is likely not wearing a collar and, although friendly, can be shy around strangers.

"If you approach her, she might run away, and maybe that’s the reason if nobody has her, she’s on her own," Lionel Lun said.

According to the Hawaiian Humane Society, where the couple filed a lost dog report as well as one with the police, there were 2,969 reports of lost dogs in the year ending June 30, 2013. Only 638 were found.

"A collar with a tag with your telephone number and a microchip in which your contact information is current with us is so simple, so cheap and so important," said Jacque Vaughn, community relations director. "The majority of animals that arrive to us are stray — many of which are potentially lost with no ID."

The society recommends microchipping, which unlike an ID tag is permanent.

In addition to filing a lost pet report with the society, Vaughn said, owners should also visit shelters every day to see if their pet is there.

"It’s not enough to call and ask rescue organizations to keep an eye out for your missing black cat. Go look for yourself. There’s just too many animals, and descriptions are highly subjective," she said. "People are coming here every day to search for their pet."

According to its website, the humane society will keep unidentified animals for 48 hours before they are eligible for adoption.