With a gun in his hand, Norman Bonds walked past a man at the Southern Avenue Metro station and said only one word: “Move,” according to court papers. In the bus bay nearby, the man saw Harold Detter fall face down into the ground.

Norman Bonds escorted by police detectives (Matt Zapotosky)

But why Bonds, a 32-year-old from the Hillcrest Heights area with a lengthy criminal record, allegedly shot Detter, a 43-year-old father and IT professional who family members believe was on his way home from work, remains a mystery. The police charging documents do not shed any light on the question of motive, which police officials have said they are still probing.

According to police officials and the documents, Bonds approached Detter and shot him in the head. The two men did not exchange words — nor did Bonds rob Detter — and investigators are probing whether they knew each other, police officials have said. Detter’s family members have said they had never heard of Bonds, and Bonds’s grandmother has said she had never heard of Detter.

Also Thursday, a Prince George’s County police spokeswoman announced on Twitter that detectives had recovered what is believed to be the weapon used in the shooting. The spokesman Tweeted that ballistics tests were being performed to determine a definitive link.

Bonds, who was arrested Wednesday morning, is scheduled to appear in court for a bond hearing Thursday afternoon.

More from The Washington Post:

Crash that killed mom, 5-year-old claims girl’s life

8,000 Pr. George’s diplomas marred by typo

D.C. traffic cameras rake in $55 million