Senate Judiciary Committee Chairman Chuck Grassley on Thursday asked the Department of Justice to provide more information about text messages that revealed an anti-Trump, pro-Clinton bias among officials who were working on investigations into the two presidential candidates.

Officials delivered text messages between Peter Strzok, who was on special counsel Robert Mueller's team before being demoted, and Lisa Page, a lawyer who was also assigned to Mueller's probe but has since been removed. Strzok and Page were having an affair, and revealed their political leanings in texts between each other.

Grassley, who had already requested an interview with Strzok in October, asked Deputy Attorney General Rod Rosenstein in a letter to disclose when and how the department became aware of the text messages. He pointed out two text messages that particularly bothered him.

One from Strzok to Page reads: “I want to believe the path you threw out for consideration in Andy’s office – that there’s no way he gets elected – but I’m afraid we can’t take that risk. It’s like an insurance policy in the unlikely event you die before you’re 40 ...”

Grassley said he assumes “Andy” means Deputy FBI Director Andrew McCabe, which is concerning to him that whatever was being discussed extends past just Strzok and Page, and shows the two talking about taking some “official action” to guard against a Trump presidency while in McCabe's office.

Another text message from Page to Strzok said Strzok had advised that "we text on the phone when we talk about hillary because it can't be traced." Grassley said it's worrisome because it was just before Strzok interviewed former Hillary Clinton aides Huma Abedin and Cheryl Mills as part of the email investigation.

“Any improper political influence or motives in the course of any FBI investigation must be brought to light and fully addressed,” Grassley wrote in his Wednesday letter, one day after the deputy attorney general testified before the House Judiciary Committee about the special counsel’s probe.

Grassley asked to know when exactly Strzok and Page were removed from Mueller’s team, and demanded other records relating to the conversation about about McCabe. He also asked for all records relating to McCabe’s communications with Strzok and Page.

“What steps have you taken to determine whether Mr. Strzok, Mr. Page, and Mr. McCabe should face disciplinary action for their conduct?” Grassley asked.

Grassley, whose committee is already investigating any improper political influence and bias in the Justice Department or FBI, asked if Rosenstein has taken any steps to see if anything was done during the campaign to escalate the Russia investigation that "might have been a result of the political animus evidenced by these text messages rather than on the merits."

Grassley and other Republicans are worried that Mueller's team is biased against Trump and Republicans. But Rosenstein told the House Judiciary Committee Wednesday that he is not aware of any "impropriety" in Mueller's team.

"We do have regulations and the special counsel is subject to all the department's rules and subject to oversight by the department, including the inspector. I’m not aware of any violation of those rules by the special counsel employees," he explained.