The largest police union in Texas is warning cops in the town and school district of Uvalde to “cooperate fully” with investigations probing the delayed efforts to end last week’s slaughter at Robb Elementary School.

The Combined Law Enforcement Associations of Texas (CLEAT) made the scathing announcement late Tuesday, soon after reports claimed that police officials in the small south-central Texas town have stopped cooperating with a state police investigation.

Investigators confirmed they are still trying to interview local schools police chief Pete Arredondo, who was named as being in command when officers waited close to an hour to storm the gunman who killed 19 kids and two teachers at the school last week.

In its statement, CLEAT said it “is advising our members to cooperate fully with all official governmental investigations into actions relating to the law enforcement response to the Uvalde mass shooting.”

It also called for “a strong, independent investigation by the US Department of Justice with assistance from the FBI” to “discover what really happened.”

They also blasted police officials for dispensing bogus info to the public and to state leaders in the early days after the attack — information that prompted Texas Gov. Greg Abbott to say he had been “misled.”

“There has been a great deal of false and misleading information in the aftermath of this tragedy. Some of the information came from the very highest levels of government and law enforcement,” CLEAT noted.

“Sources that Texans once saw as iron-clad and completely reliable have now been proven false. This false information has exacerbated ill-informed speculation which has, in turn, created a hotbed of unreliability when it comes to finding the truth,” the union raged.

The union stressed that it stands behind “those professionals who put an end to the assault on Robb Elementary.”

“Without the officers who breached the door and took out the murderer, this already devastating event would have lasted longer and more children would have been lost,” CLEAT said.

Still, it stressed: “Law enforcement agencies in Texas are para-military and operate in a chain-of-command structure. … Officers swear an oath to protect and serve in a para-military setting where they, as individuals, do not get to make the final decisions.”

In one of the first major press conferences after last week’s massacre, Abbott had joined police officials in insisting officers had shot dead teen gunman Salvador Ramos as quickly as possible, praising them for saving lives.

However, mounting evidence showed officers waited more than an hour to get him — even as trapped kids desperately called 911 from inside, begging for help. Once the truth emerged, Abbott said he was “livid” over getting bad info.

Officials later admitted that they made the “wrong decision” in waiting, while also changing a slew of key details, including whether Ramos was confronted and how he got through an unlocked school door.