An investigator hired by the University of Texas to look into an allegation that a state lawmaker sent a sexually explicit text and picture to a graduate student has found that the "available evidence" does not show that Sen. Charles Schwertner violated university policy but added that he did not fully cooperate with the probe.

A three-page executive summary from a broader investigative report by former U.S. Attorney Johnny Sutton said Schwertner blamed another person for sending the messages but repeatedly declined to identify that person.

Schwertner "has access to information that could allow a more definitive conclusion to this matter, but (he) is unwilling to share that information and the University lacks authority to compel him to investigate more fully," Sutton concluded.

The report said that a forensic analysis of a phone provided by Schwertner confirmed that the message and photograph were not sent from his primary cellphone but also said it's possible he sent the messages from a second device.

Schwertner and his lawyer released statements Tuesday evening, saying the UT report clears the senator of wrongdoing.

"I do not condone sexual misconduct of any kind. The University of Texas has closed their investigation because I did not send the offensive text messages in question," Schwertner said. "This unfortunate matter is now closed."

The report, however, does not offer a conclusion about whether Schwertner or a third person committed wrongdoing but instead said that investigators could not determine that Schwertner violated university policy based on the evidence shared with them by the senator and the student. The report also noted that Schwertner declined to speak with investigators or respond to five written questions "that were designed to bring clarity."

The statement from Schwertner's lawyers, David and Perry Minton, said that the senator wanted to answer more questions from the investigators but did not do so on the advice of the Mintons, who believed that UT did not handle the investigation fairly.

The student met Schwertner, a Georgetown Republican and a UT alumnus, at a university-affiliated event and told him she was interested in working at the Legislature, three senior UT officials told the American-Statesman in September. After the event, Schwertner and the student exchanged messages on the networking site LinkedIn before moving to text messaging, two of the officials said.

The student complained after Schwertner appeared to interrupt an otherwise professional exchange with a sexual proposition and an image of a man's genitalia, two of the sources said.

In response to a public records request, UT on Tuesday released copies of the exchange that were provided to investigators by the student. They show a message from the number Schwertner gave the student saying, "Sorry. I really just wanted to f--- you" and include a redacted image.

The student replied, "Please stop. This is unprofessional. I'm a student interested in learning about Healthcare Policy. These advances are unwanted."

Schwertner has denied that he sent the text or image to the student since the Statesman in September first reported that UT was investigating him. But, he had not previously offered an explanation for what led the student to complain to UT officials about his conduct.

The UT report for the first time lays out Schwertner's explanation, saying that the third person used his account for a smartphone app called Hushed. The app allows users to communicate without revealing their real cellphone numbers by creating proxy numbers. Users can send text messages from the app using the alias numbers, and receivers do not know that the sender isn't using a regular cellphone number.

The newly disclosed records include one of Schwertner's business cards, provided to investigators by the student, with a handwritten phone number on it. The number matches the alias phone number associated with Schwertner's Hushed account, the one that sent the messages and image to the student in the exchange.

Sutton wrote that according to Schwertner, the third person had access to his account information, including his password, and sent the graduate student messages without his knowledge or authorization. The forensic analysis of Schwertner's phone commissioned by Sutton's probe indicated that the senator may have shared a Hushed account with the third person in order to "privately communicate between themselves."

"The attorney for this third person did not disclose this third person's relationship with (Schwertner) and did not reveal why he or she sent the offensive text message and photograph," the report said.

Neither Schwertner nor the attorney would reveal the third person's identity, leading Sutton to say it is impossible to reach a conclusion on the senator's explanation.

"We recognize that it is plausible (Schwertner) sent the text messages and photograph from a device other than his personal cell phone and the third person claiming responsibility is being untruthful or does not exist, but we have no evidence to support those possibilities," Sutton wrote. "It is also plausible that the third person who claims to have sent the text messages and photograph does exist and did in fact send them."

Schwertner, whose 10-county Senate District 5 includes Williamson and Brazos counties, won a new four-year term in the Nov. 6 election against Democrat Meg Walsh.