AP Photo/Jacquelyn Martin
Ted Cruz.
Cruz called Trump a "sniveling coward" to a gaggle of reporters.
"I don't get angry often, but if you mess with my wife, if you mess with my kids, that will do it every time," he said. "Donald, you're a sniveling coward and leave Heidi the hell alone."
A reporter then immediately asked Cruz if he would still support Trump as the nominee should he win. Cruz has said he would support the Republican nominee.
"I'm going to beat him for the nomination," Cruz insisted. "Donald Trump will not be the nominee."
Late Wednesday night, Trump tweeted out someone else's photo that depicted Heidi Cruz with an unflattering scowl. Next to that photo was one of Melania Trump. The text, which Donald Trump blasted out to his seven million followers: "A picture is worth a thousand words."
Trump adviser Stephen Miller defended the post during a CNN interview the next day by saying that "the retweet speaks for itself."
The Trump campaign has also suggested that the image and Trump previously threatening to "spill the beans" on Heidi Cruz were retaliation after an anti-Trump super PAC, not affiliated with Cruz's campaign, used a racy photo of Melania Trump in one of its ads.