A state and local police investigation remains ongoing after two wells at the site of a planned 20-unit rental development in Tisbury were found contaminated with motor oil last week.

The incident at the Island Housing Trust’s Kuehn’s Way development is being investigated by Tisbury police, state environmental police and the state Attorney General’s environmental crime bureau. So far no leads have turned up, after interviews with neighbors and others, according to Tisbury police chief Mark Saloio.

“This is still an active investigation,” Chief Saloio told the Gazette this week.

Tisbury Det. Bill Brigham is assisting with the investigation, along with environmental police and Det. Andrew Lieberwirth with the A.G’s office, the chief also said.

The IHT board of directors is offering a $5,000 reward for information leading to the conviction of the person or persons who tampered with the wells, executive director Philippe Jordi said last week.

The wells have been plugged, capped and decommissioned by environmental engineers to remediate the situation, the IHT also said in a statement.

“We’re pretty confident that the aquifer has not been contaminated, but it’s pretty disturbing,” Mr. Jordi said.

Chief Saloio said the motive behind the incident remains unknown. “We don’t know whether it was a hate crime or a random act of malicious destruction,” he said.

The two wells were drilled in January to serve as the public water supply for the Kuehn’s Way development, a neighborhood of 20 rental apartments scheduled to begin construction this spring. The project is located off State Road in Tisbury across from the Assembly of God church.

The first well was found to be contaminated with motor oil when required state environment testing was conducted on Jan. 26, Mr. Jordi said. The second well tested clean at that time, but was found to be contaminated in subsequent testing done.

Underground monitoring wells have been installed near the tampered wells and abutting properties for water quality testing, and Mr. Jordi said the trust is securing the site with fencing and additional protections and will be drilling two new wells.

Though the contamination will add unexpected costs, he said it has not altered the timeline for construction of the Kuehn’s Way neighborhood, which is scheduled to open in early 2022.

Mr. Jordi said the IHT board meets this weekend and is expected to discuss the incident.

“We’ll be discussing it further with them,” he said. “We have various security and surveillance in place and planned as we continued to develop the site further.”

Anyone who may have information about the crime is asked to contact Detective Lieberwirth at 617-963-2657.