The girlfriend of a man shot dead by police as he chewed the face of a homeless person has spoken out for the first time in public, saying he was deeply religious and studied the Bible and Qur'an with her.

Yovonka Bryant, who says she shared a relationship with Rudy Eugene before his death during the grisly attack 11 days ago on a Miami causeway, said there were no warning signs that he was about to go off the rails.

"I felt safe with Rudy. We spoke about marriage and I thought that he would be a good father to my children," Bryant, 27, told reporters at a press conference in Miami organised by the celebrity lawyer Gloria Allred.

"Rudy and I never discussed cannibalism or voodoo. I believe that he would never knowingly and intentionally have inflicted the harm that he did and that most likely there is a drug that he was given without his knowledge that caused him to do what he did."

The naked Eugene, 31, ripped off almost 80% of Ronald Poppo's face with his teeth during the incident in which he growled at police officers before being shot six times and killed. There has been speculation that he had taken a toxic synthetic drug called bath salts, which has similar mind-altering effects similar to LSD but which can also induce feelings of severe paranoia, depression and superhuman strength.

Bryant, a single mother with children ages 11, eight and three, said that her boyfriend, to whom she last spoke to the day before his death, was not a serious drugs user. She said: "Rudy never drank alcohol or used drugs around me. I only saw him smoke a marijuana cigarette once."

A police source said Wednesday that toxicology reports on Eugene's body might not be ready for at least another two months but that the preliminary autopsy report indicated that he had recently used marijuana.

Additionally, Eugene's purple car, found close to the MacArthur Causeway decked in Haitian flags, contained a Bible, and several pages torn from it were found fluttering close to the scene of the attack, the source told Miami's CBS4 News.

Also found in the car were five empty bottles of water, which police believe were newly purchased. One of the effects of taking bath salts is a significant rise in body temperature, and users often report they feel like their internal organs are burning up, drug experts say.

Eugene's victim, meanwhile, remains in a serious condition at Miami's Jackson Memorial Hospital. Poppo is said to be conscious but apparently still not yet fully aware of the severity of the attack on him.

Bryant, who works as an administrative assistant for an accountant, said she wanted to speak out to "clear up the confusion" since the episode.

Allred said that Bryant was not the anonymous "girlfriend" of Eugene quoted in a newspaper last week, who said she last saw him on the morning of the attack, but someone who had forged deep bonds.

"She thinks it is important that the public know the truth about Rudy Eugene and her relationship with him," said Allred, who would not address questions over whether Bryant had or would profit from coming forward.

"She is a victim too and has suffered the loss of someone she really loved. We have many witnesses to their relationship. She had no indication that he had any mental illness."

The relationship, Bryant said, began in March, and Eugene, a keen sports fan, had enjoyed family games and movie nights with her family. "We took my children to the park, we dined in restaurants, and we often engaged in debates over what God really meant to people," she said.

"He played football with my brothers and cousins every Saturday afternoon. My children used the nickname 'Uncle Beard' when they talked about him. One of the things I loved about Rudy was how he talked about his family and how much he loved his mother and grandmother. I truly did not have a care in the world when I was with him."

Eugene, she added, had "dreams and goals" in life. "One was to start his own car detail company. He also dreamed of having a family life," she said.

"I am devastated by his loss, and my heart goes out to the homeless man who became an innocent victim in this tragedy."

Allred stated that she and Bryant were both "very concerned about the issue of cannibalism", citing other recent high-profile cases in the US, Canada, Japan and Sweden.

"Jokes are being made about this issue on late-night television, but cannibalism is a serious issue," she said. "It is very important that the social taboo and stigma that have long been attached to this subject continues and that society condemns cannibalism, rather than trivialising or glamorising it."