Family alerted police on driver

Guaman was allegedly drunk when his Ford pickup collided with a motorcycle ridden by Matthew Denice, 23, of Milford at Congress and Fayette streets about 7:50 p.m. Saturday. Guaman’s 6-year-old son sat next to him in the truck.

As Guaman appeared in court, Denice’s family cried from the front two rows.

Bail was set at $100,000, and Guaman remains in Worcester County jail. He is scheduled to appear in court again Sept. 12. Craig Tavares, Guaman’s court-appointed attorney, declined to comment yesterday because he is not permanently assigned to the case.

The arrest of Guaman and reports that he previously faced criminal charges raised concern about why he had not already been reported to immigration authorities, and highlighted the ongoing debate over a federal initiative to identify illegal immigrants.

Milford police arrested Guaman in 2008 on charges of assault and battery on a police officer and at least one public employee and of breaking and entering, according to the police and the Worcester district attorney’s office. The case was continued without a finding for one year. Police said he also faced a few minor traffic charges dating to 2007, but the district attorney’s office could not confirm that information.

Some officials said the case showed why Massachusetts should embrace the federal program known as Secure Communities, a computer-based system launched in 2008 that automatically cross-checks the fingerprints of everyone who is arrested against immigration databases, alerting immigration authorities so they can take action against those here illegally.

“It’s a textbook example of why we need to join Secure Communities,’’ said Worcester Sheriff Lewis Evangelidis. “This is what we are trying to avoid.’’

State Senator Richard T. Moore, a Democrat from Uxbridge, wrote Governor Deval Patrick yesterday urging him to crack down on illegal immigrants driving without a license.