The US Department of Justice is working with federal agencies to investigate allegations made by a Texas police officer in an email to his superiors, in which he described how he and his partner were ordered to push migrants into the Rio Grande River and were denied water despite the blistering heat.

In a statement to NBC News on Thursday, Justice Department spokeswoman Xochitl Hinojosa said the department «is aware of the troubling reports» and is working with the Department of Homeland Security and «other relevant agencies to assess the situation.»

In a July 3 email obtained by NBC News on Tuesday, a police officer with the Department of Public Safety expressed concern about these alleged warrants.

The email, detailing a series of interactions law enforcement had with migrants at Eagle Pass from June 24 to July 1, also provided information about how the use of barbed wire traps and buoy barriers under Gov. Greg Abbott’s border security initiative known as Operation Lone Star has further endangered the lives of migrants.

In his email to his superiors, the policeman said that the border control actions «have crossed the line towards the inhumane».

The content of the patrolman’s email was first reported by the Houston Chronicle on Monday.

Texas Department of Public Safety officials have denied the existence of any directive, policy or order instructing soldiers to push migrants back into the river or deny them drinking water.

«No orders have been issued under this mission that would compromise the lives of those attempting to cross the border illegally,» Abbott said in a joint statement on Tuesday.

Texas DPS has said an internal investigation is underway. The Texas Office of the Inspector General is also investigating the claims.

The Department of Homeland Security did not respond to a request for comment.

The email obtained by NBC News did not include the name of the officer or who the email was sent to.

On June 25, the police officer said he and a colleague encountered a group of 120 migrants, including young children and nursing mothers. According to the email, they were ordered to «push people back into the water to go to Mexico.»

The police officer wrote in the email that he responded to «the very real potential for exhausted people to drown.» Despite this, the officer and his partner were ordered to leave, according to the officer.

On June 30, the police officer said he witnessed a 4-year-old girl attempting to cross through barbed wire being «rejected» by Texas National Guard soldiers in accordance with warrants. The boy then passed out from the extreme heat, according to the email.

Earlier that day, according to the trooper’s email, a man with a major laceration to his leg said he was injured trying to save his son, who had gotten stuck in the barbed-wire barrel trap in the river that is used as a barrier. Another 15-year-old boy broke his leg in one of the traps, which were set in a way that «forced him into the river, where it is not safe to travel,» according to the email.

The policeman said he also encountered a 19-year-old woman who had been cut with a wire and was having a miscarriage.

The patrolman drew attention to how the placement of the barbed wire traps pushed people to travel through the deepest and most unsafe areas of the Rio Grande. The conditions caused at least five people to drown or go missing that week, according to the email.

The soldier urged his superiors to «provide a safe means of travel on the mainland to the appropriate collection points.»

The allegations come after Abbott authorized more than $4 billion for Operation Lone Star, which also includes transporting thousands of migrants to cities led by Democrats and Arrest of immigrants for trespassing.