TEL AVIV — Israel revealed new details Sunday of an investigation into the oil spill that washed up roughly a thousand tons of tar on its shoreline and caused potentially irreversible ecological damage to the region's marine wildlife and biodiversity.

Officials from Israel’s Environmental Protection Ministry conducted a surprise inspection Saturday of the Minerva Helen, one of the Greek tankers suspected in the spill, while it was docked at the Piraeus port in Athens. The next day, after an Israeli court-
issued gag order on the names and details on the suspected ships was lifted, the ministry announced the Minerva Helen was no longer considered a suspect.

“The pollution has a source,” Environmental Protection Minister Gila Gamliel said in a statement. “We will not ignore this environmental crime and will take all measures to locate the criminal.”

The investigation, conducted in cooperation with Greek authorities, has been underway since at least mid-February, when reports surfaced of massive amounts of sticky black tar appearing along Israel’s 120-mile stretch of shoreline. Ten ships were initially suspected as potential culprits, but the number has expanded to dozens, the ministry said.

The spill is believed to have occurred between Feb. 6 and 10. It has been described as one of the “worst ecological disasters” in Israel’s history.

Researchers from Hebrew University last week analyzed samples collected from a beach in the central Israeli city of Bat Yam. They reported that the source of the pollution was likely to be crude oil, corroborating the previously reported theory that the spill was the result of a tanker leak or an accident during the transfer of oil from one vessel to another.

Israeli Prime Minister Benjamin Netanyahu said last week that he has allocated around $14 million to clean up Israel’s beaches. Analysts say the effort could take several months or years.

“We must act quickly, before it seeps into the ground, especially in rocky areas,” Netanyahu said. “This is damage that will stay with us for many years to come.”

Israel’s Nature and Parks Authority has said a young, 55-foot-long fin whale and six baby sea turtles have died of tar poisoning. Six other sea turtles have been rehabilitated at the Sea Turtle Rescue Center in Michmoret in central Israel. They were fed mayonnaise to help flush out the tar that stuck to their digestive tracts.

Within days of arriving on Israel’s shores, the pollution also spread to nearby Lebanon, from the border town of Naqourah to the southern city of Tyre, where the Tyre Coast Nature Reserve serves as an important nesting site for endangered loggerhead and green sea turtles.

“The nature reserve is suffering from approximately two tons of tar, 90 percent of which is hidden under the sand,” Mouin Hamze, director of the reserve, told reporters on Saturday.

On Saturday, Israeli Air Force drones identified another possible oil spill, some 100 miles west of the northern Israeli city of Haifa. That spill appeared to be moving away from the coastline.

Jonathan Aikhenbaum, the director of Greenpeace Israel, which is conducting an independent investigation, said the spill should not be seen as an isolated incident.

“The writing was on the wall,” he said. “Now, we must take all the lessons from this crime and bring to justice those who committed it, and also ensure that plans for construction of dangerous oil infrastructures be canceled immediately, to prevent such incidents in the coming years.”