Supporters of Texas Democrat Senate candidate Beto O'Rourke in a Dallas County neighborhood received postcards showing the image of a bloody fetus in their mailboxes, the Dallas Morning News reported.

"We were horrified and just, like, gut-punched to see that image," Angela Fuller Heyde of Garland told the Morning News.

The postcards were found in the mailboxes of residents who had O'Rourke campaign signs in their yards.

O'Rourke is in a contentious race to unseat Republican incumbent Ted Cruz in the mid-term elections next month.

What's the story?

On Wednesday, residents including Fuller Heyde found a black envelope in their mailboxes addressed to "Beto supporter," along with the home's address.

The envelopes were stamped but they had no postmark, Fuller Hyde told the newspaper.

Inside the envelope, the postcard had the following message:

"Beto O'Rourke is not pro-choice, he is PRO-ABORTION! He wants more dead babies. He voted against the Born-Alive Abortion Survivors Protection Act; He voted against the Pain-Capable Unborn Child Protection Act; He voted against a ban on abortion after 20 weeks," the postcard read, according to the Morning News.

Then, beneath it was another message in all capital letters.

"Stop killing innocent unborn children. Your vote for O'Rourke is your vote for more abortion."

The lower half of the postcard showed a photo of a bloody fetus that was purportedly aborted during the first trimester.

Then, beneath it was another message in all capital letters.

"Stop killing innocent unborn children. Your vote for O'Rourke is your vote for more abortion."

The postcards also had a web address for the Center for Bio-Ethical Reform, a California-based anti-abortion organization.

What else did the residents say?

Fuller Heyde, who described herself as a progressive Democrat to the Morning News, said that she felt threatened by the letter.

Another resident, Leigh Taylor, received the postcard in her mail Friday.

Taylor believes the letter may have been hand-delivered because she has "informed delivery" and she never received a preview of the envelope.

"I was pretty afraid to put my sign up until I saw others doing it," Taylor told the newspaper, adding that she suspected someone drove through the neighborhood scouting for O'Rourke signs.

She said the neighborhood is "pretty traditionally Republican."

What else?

Fuller Hyde reported the postcard to local authorities.

Garland police Lt. Pedro Barineau could be considered as a type of harassment or possible mail fraud.

"It does qualify as a type of harassment, but the investigation would be difficult and it would probably be difficult to track down the offenders," Barineau said.