Indiana Republican Reps. Todd Rokita and Luke Messer are upping the pressure on their shadow war ahead of their likely Senate bids in new barbs, ahead of what’s expected to be a rough primary.

Messer on Monday sent his supporters a lengthy email defending himself from Rokita’s accusations with the subject line “I’m tired of Todd Rokita lying about my family.” He called Rokita’s attacks “especially remarkable” because of their long history — they went to college together before serving together both in Indiana and in Congress.

“For months, Todd Rokita has spread lies and half-truths about my family, claiming we are not Hoosiers and attacking my wife’s legal career,” Messer wrote.

“It’s clear that he will do and say almost anything to advance his political career. Apparently, truth or integrity won’t get in the way.”

While both men have not yet announced whether they’ll run, the constant sniping in the news and among their allies has only increased speculation that they’ll jump in.

{mosads}Both camps have accused one another of planting negative stories about them in the media — Rokita was dogged by a Politico report that he spent campaign funds on a private plane while Messer was put on the defensive by an Associated Press story that notes that Messer’s wife made almost $600,000 from a city consulting contract with an Indiana city while living in Virginia.

Messer’s email goes on to defend himself against attacks Rokita has levied based on that story, as he looks to shore up his defenses in case he runs. He points to his background as a child in a single-family household to explain why his kids go to school in the D.C. area and why he owns his house in the district with his mother.

“For me, the choice was easy. Growing up in a single-parent family without a Dad at home, I knew first-hand that children need a full-time father,” he wrote.

“We have never hidden any of this from our constituents.”

And he defended his wife and accused Rokita of trying to “destroy my wife’s career for his own political gain.”

Tim Edson, a spokesman with Rokita’s campaign, responded to Messer’s letter by calling it “unhinged.”

“Todd Rokita had nothing to do with the Associated Press reporting. Messer thinks pounding the table and feigning outrage can make people overlook very real vulnerabilities that Donnelly and national Democrats will savagely exploit,” Edson said of Democratic Sen. Joe Donnelly, the current incumbent.

“Now we can add a ticking time bomb to the list of Messer’s vulnerabilities … Republicans deserve a candidate who can win, not one blinded to his vulnerabilities by arrogance.”

The letter comes days after Rokita skewered Messer in a local news interview with Fox 59, an interview where Messer says Rokita “directly attacked my wife and family.”

In that interview, Rokita laid into Messer over the Associated Press story, jumping on the fact that Messer recently sat for an interview with the news station by satellite to jab at Messer’s residency.

“He did it by satellite, I’m sitting here person to person with you. That’s because Luke Messer doesn’t live in the state, I do,” Rokita said.

“I’m accountable to voters and taxpayers here, I live amongst them every week … I don’t have the baggage Luke Messer does.”

Also, this weekend, Rokita’s camp needled Messer for a lackluster fundraising quarter where Rokita outraised Messer by more than $450,000.