A disgruntled lawyer possessing two weapons and more than 2500 rounds of live ammunition has shot six drivers in a Houston neighbourhood, before eventually being killed by police.

Another three people had injuries from glass or debris.

The gunman was wearing military-style apparel with old Nazi emblems during the Monday shootings, Houston Homicide Captain Dwayne Ready said at a news conference.

Vintage military items dating to the Civil War and other guns were found the man’s apartment.

Ready and Interim Police Chief Martha Montalvo did not identify the man and did not have information about a motive.

Nine people were injured; one person is in critical condition and another in serious condition, officials said.

Authorities first received reports of the shootings about 6.30am, and the man began firing at officers when they arrived.

The man had two legally purchased guns – a .45-calibre semi-automatic handgun and a tommy gun – plus an unsheathed knife, Ready said. He also noted that there were 75 spent casings at the scene, which were from officers and the gunman.

Mayor Sylvester Turner told KTRK-TV the man was a “disgruntled” lawyer and was “either fired or had a bad relationship with this law firm”.

But his former law partner, Kenneth McDaniel, disputed that assertion, saying they jointly closed their 12-year-old law firm in February due to economic conditions related to Houston’s energy industry downturn.

McDaniel also said he’d had no contact with the man recently and that police called him on Monday morning to check on his safety, though they didn’t explain why.

“He went his way with his practice and I went with mine,” McDaniel said, adding, “All I can say it’s a horrible situation. I’m sad for everyone involved.”