PHOENIX -- Police investigating eight deadly attacks blamed on the "Baseline Killer" have arrested a man in two 2005 sexual assaults connected to the case, authorities said Thursday.

Police have forensic evidence to connect the 42-year-old man, identified as Phoenix resident Mark Goudeau, to two sexual assaults that occurred on Sept. 20, said Phoenix Police Chief Jack Harris.

Harris emphasized that Goudeau hasn't been connected to any of the other crimes in the string attributed to the Baseline Killer. But he said police were following up on other possibly related crimes.

"We still consider all those other cases open at this point," said Sgt. Andy Hill, a spokesman with the Phoenix Police Department. "The investigation is continuing and we have a lot of work ahead of us."

Goudeau was booked into jail while witnesses from the 2005 incident had been called to do a photo lineup, Hill said.

Previously released police reports said that it was two sisters, ages 21 and 23, who were sexually assaulted on Sept. 20 during a nighttime walk in a park in southwest Phoenix.

After the women had put their feet in playground sprinklers to cool off, a man with a baseball cap lowered to his eyebrows came from behind them and appeared angry and agitated. The attacker pointed a gun at the two women during the encounter. One of the victims was six months pregnant at the time of the attack, according to police reports.

Cmdr. Kim Humphrey said the suspect resembles a widely circulated police sketch depicting the Baseline Killer as a man with dreadlocks. But he emphasized the man was only being held in two sexual assaults.

"As far as the other crimes in the series, we would have to say that at this time we need people to continue to be vigilant," Humphrey said.

"We are not slowing down, we are not pulling back," he said. "We are going to continue to put together the effort that we need to find out whether or not this individual and/or any other individuals are involved in that series of crimes."

Stay with KPHO.com and CBS 5 News for further late-breaking developments.