A New Jersey lawyer already charged in connection with a series of sexual assaults in Boston's Charlestown neighborhood about 15 years ago pleaded not guilty on Thursday to new charges stemming from sexual assaults in another area of the city that occurred at roughly the same time.

Matthew Nilo, 35, was released on $50,000 bail at his arraignment in Suffolk Superior Court after entering pleas to a total of seven new charges, including rape, aggravated rape and assault to rape.

The new charges stem from five attacks on four women — one woman was attacked twice — in Boston's North End between January 2007 and July 2008, prosecutors said. Nilo lived in the neighborhood at the time, Suffolk District Attorney Kevin Hayden said, and the attacks followed a similar pattern to the Charlestown cases.

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Nilo was previously freed on $500,000 bail after pleading not guilty in June in connection with the Charlestown attacks. He worked for a New-York-based cybersecurity company, was hired in January after passing a background check, and was suspended following his arrest.

Advances in DNA testing and genealogical testing led to identifying Nilo, who now lives in Weehawken, New Jersey, as a suspect, Hayden said.

“Nothing can eliminate the terror experienced by these survivors,” Hayden said after the arraignment. “But at least now they have the knowledge that Mr. Nilo must answer to the horrible charges he’s alleged to have committed. We hope this provides some solace to survivors of these attacks.”

Nilo’s attorney, Joseph Cataldo, said his client denies the charges and the district attorney's office was “piling on.”

“I think they’re trying to solve some unresolved cases, and I’m afraid that the government might be piling on, just trying to claim that Mr. Nilo committed these crimes,” Cataldo said outside the courtroom.

Nilo was tied to the Charlestown cases through DNA taken from a drinking glass he had used at a corporate event this year, and Cataldo has questioned the constitutionality of the way that evidence was collected without a warrant.

Hayden thinks it will stand up in court.

“We're confident in the legality of the evidence we have recovered," Hayden said.

Nilo is scheduled to be back in court on Sept. 14.