(NEW YORK) -- The adoptive parents of missing Isabella "Ariel" Kalua have been arrested and charged with second-degree murder after more than two months of investigations, according to the Honolulu Police Department.
Isabella would have turned 7 years old last week.
"It's clear that [Isabella] was loved and missed by many people," said Rade Vanic, HPD's interim police chief. "Unfortunately, what began as a search for a missing girl turned into a murder investigation focused on the Kaluas. We believe that the evidence leads to the Kaluas and no one else."
She was first reported missing on Sept. 13 in Waimanalo, Hawaii. HPD, the FBI and community members searched for Isabella for more than a week.
"Her photo and story touched the hearts of many in the community," Vanic said. "We thank all of you for your efforts and concerns."
Isaac and Lehua Kalua were arrested Wednesday. Investigators allege the couple murdered Kalua in mid-August, a month before she was reported missing. Police claim the Kaluas lied in their initial report, saying they last saw Isabella on Sept. 12 -- a day before she was reported missing.
The Kaluas are being held without bail and will make their first court appearance on Friday.
Isabella's four siblings have been taken into the custody of Child Welfare Services, according to police.
Isabella's remains have not yet been recovered.
Lawyers for the Kaluas couldn't immediately be reached by ABC News.
Investigators are urging anyone with information, including witnesses or people who had contact with Isabella and the Kalua family between August and September, to come forward.
Anyone with information is asked to call Crimestoppers at (808) 955-8300.
Anyone who may have witnessed neglect or abuse against the Kalua children is urged to call Child Welfare Services at 1-888-380-3088.