Fort Hood, Texas (CNN) -- Witnesses at a military hearing Thursday said the suspect in last year's Fort Hood shooting rampage told a gun shop he wanted the most technologically advanced handgun available and one with large-capacity ammunition magazines.
The prosecution in the Army hearing ended its case late Thursday morning, presenting new details of how Army Major Nidal Hasan bought a gun and ammunition and practiced how to shoot.
The military proceeding, called an Article 32 hearing, will determine whether there is sufficient evidence to proceed to a court martial, with a possible penalty of death.
Hasan bought an FN 5.7 semi-automatic in August 2009 from the Guns Galore store in Killeen, Texas, according to witnesses. That's the handgun authorities say he used to kill 13 people November 5 and wound dozens more.
The hearing has been recessed until November 15, when the defense will have its chance to call witnesses.
The investigating officer in the case, Col. James Pohl, who acts at a judge or presiding officer, granted a new delay in the case to allow a psychiatrist hired by the defense to conduct a mental evaluation of Hasan.
Thursday was the seventh full day of the Article 32 proceedings.
In Thursday's testimony, Hasan's voice was heard for the first time in the small military courtroom since the proceedings began. The suspect is heard saying "OK" and "Oh" on a cellphone video that he recorded as he was buying a handgun and the salesman explained where the safety was and how to clean the weapon.
Another customer in the store told how he had talked with Hasan for more than 45 minutes.
"He asked one question -- what's the most technologically advanced handgun?" Army Specialist William Gilbert testified.
"I asked him, 'What's your intended purpose?' " Gilbert said.
Hasan gave no answer, according to Gilbert, but said his two specifications were the most technologically advanced handgun and a high magazine capacity.
Gilbert said he talked with Hasan about the controversy surrounding the gun -- whether its bullets could penetrate body armor and how its high-velocity rounds created large wounds.
"He said my information had been very, very helpful and he thanked me and he walked out," Gilbert said.
Gilbert said he is studying to become a military policeman.
Another prosecution witness, John Choats, part owner of a private shooting range, said he instructed Hasan in a concealed-weapons class. He said Hasan was a frequent visitor to the range.
"He's the gentleman sitting right there," Choats said, standing up and pointing at Hasan, who was sitting in a wheelchair at the side of the defense table.
"He came out about once or twice every week," Choats said, describing how Hasan practiced and improved his aim with his handgun on the 100-yard rifle range, selecting silhouette targets.
"It was up to the major," Choats said about the targets.
Hasan often returned to the gun store, where he bought more ammunition and magazines.
"He was apparently shooting quite a bit," former gun salesman Frederick Brannon said.
Brannon testified Hasan said he didn't want to take time at the range loading and instead loaded magazines in advance while watching TV. Brannon said that at times Hasan would purchase up to six or eight boxes of ammunition. With 50 bullets in a box that could be as many as 400 bullets purchased at a time.
Under defense questioning, Brannon said nothing in the sale of the handgun or ammunition was illegal or should have prompted anyone to make a special report.
Witnesses testified Wednesday how more than 200 spent shell casings were recovered at the scene of the shooting and how Hasan still had 177 bullets and a second handgun when police shot him.
The defense and prosecution continued to spar over the release of government investigations into Hasan, including his links to Muslim militants overseas and how Hasan was evaluated, promoted and transferred by his Army superiors.
At the end of proceedings Thursday, the prosecution said there were still classification issues that prevented the release of the materials.
Neither defense nor prosecution lawyers would speak with CNN outside the courtroom.
Fort Hood, located near Killeen, has more than 45,000 assigned soldiers and nearly 9,000 civilian personnel, the Army says. The base occupies 335 square miles over two counties 60 miles north of Austin.