WASHINGTON - Just what prompted Nicholas Roske to go from an alleged plot to kill Supreme Court Justice Brett Kavanaugh to calling 911 and surrendering near the justice's home is of great interest to investigators continuing to probe the alarming incident from last week. 

Court records say that after Roske flew in from California and got out of a taxi near the conservative justice's home just after 1 a.m., he saw two deputy U.S. marshals standing outside their vehicle and he walked away. But another factor may also have played an important role.

While walking along the narrow, leafy streets of Kavanaugh's dark Chevy Chase neighborhood, Roske contacted his sister, officials said.

"The suspect arrived by taxi and observed the U.S. marshals, and he turned around to contemplate his next move," according to Montgomery County Police Chief Marcus Jones. "This is when he texted his sister and told her of his intentions, and she convinced him to call 911, which he did."

The role Roske's sister may have played in upending what prosecutors say was a deeply planned attempt to break into Kavanaugh's home to kill him is the latest detail to emerge in the case of the man who federal officials charged last week with attempted murder of a federal judge.

It was just minutes after Roske's 911 call that Montgomery County police officers drove up and took him into custody. With him were burglary tools, a gun and a pair of boots with padded outer soles that could allow stealth movement inside a house, according to court records.

Roske was upset by the leaked draft of a Supreme Court opinion, supported by Kavanaugh, signaling that the court could be positioned to overturn Roe v. Wade, according to an FBI affidavit. He was also worried that in the wake of the mass shooting in Uvalde, Texas, the justice "would side with 2nd Amendment decisions that would loosen gun control laws," the affidavit states.

Several attempts to reach Roske's sister and other members of his family have been unsuccessful. His public defender previously declined to comment.

The details of what was allegedly said or texted between Roske and his sister, and how long they communicated, could not be learned. But according to court records and Montgomery County 911 recordings, approximately 33 minutes passed from the time Roske allegedly saw the marshals - and the marshals saw him - to when he called 911. During that time, he walked around the corner from the justice's home and positioned himself about 1[1/2] blocks away.

According to an affidavit written by an FBI agent: "At approximately 1:05 a.m., two United States Deputy Marshals saw an individual dressed in black clothing and carrying a backpack and a suitcase get out of a taxicab that had stopped in front of the Montgomery County, Maryland, residence of a current justice of the United States Supreme Court. The individual looked at the two Deputy Marshals, who were standing next to their parked vehicle, and then turned to walk down the street."

Roske placed two 911 calls, according to recordings provided by Montgomery's Emergency Communications Center. The first arrived at 1:38 a.m. and was very brief because the caller said he needed to read street signs to report exactly where he was. The next call came at 1:39 a.m. and yielded a police response within minutes while the call-taker stayed on the phone with Roske. Officers arrived around 1:52 a.m. to take him into custody.

Drew Wade, a U.S. Marshals spokesman, did not immediately provide comment Monday.

However quickly Roske may have decided to not go through his alleged plan, according to court records, he had spent a much longer duration putting them into motion.

Roske indicated to investigators, according to court records, that he purchased a Glock pistol and other items "for the purpose of breaking into the justice's residence and killing the justice as well as himself."

Among his belongings when he arrived outside Kavanaugh's home, according to court records, were the gun, a pistol light, tactical knife, two magazines of ammunition, pepper spray, a hammer, screwdriver, nail punch, crow bar, duct tape, the soft-soled boots and other items. It isn't clear how accessible the items were at that time.

Later, when he called 911, he indicated that the gun was inside his suitcase, according to the recordings.

"Do you have access to any weapons?" the 911 operator asked.

"Yes," Roske reportedly responded. "I brought a firearm with me, but it's unloaded and locked in the case."

"Okay. Where's the firearm now?" the operator responded.

"It's in a suitcase. It's a black suitcase," Roske said, according to the recording. "I'm standing near it, but the suitcase is zip-tied shut. I just came from the airport."