Dankert and two friends, both 23, boarded the small boat in the Seaport on Wednesday evening, officials said. When the boat struck the pier, all four were thrown onto a rocky shoreline, according to Boston Emergency Medical Services, which provided first aid to the victims.

“In difficult conditions, including darkness and slippery shoreline rocks, EMTs George May and Andrea Albano located the scene and began patient care,” EMS posted on social media. “Working in close coordination with Massport Fire, crews carefully extricated four patients from the rocks.”

Lee Gordon, a spokesperson for the Brunswick Corporation, which owns Freedom Boat Club, said the vessel involved in the crash was taken from its Seaport location “without authorization and operated outside the knowledge and control of the club, well after the club had closed for the day.”

“It was accessed without our knowledge by someone who was able to gain access to the marina,” Gordon said by email. “But it was not someone who made a reservation as we were closed for the night.”

Gordon said the company is cooperating with investigators.

Dankert played soccer at Union College in New York and graduated in 2024, the school confirmed.

“Lizzie was an exceptional student-athlete who had a tremendous impact during her four years at Union College. Her passing is a profound loss for our campus community,” a spokesperson said in an emailed statement. “We offer our condolences to Lizzie’s family, classmates, teammates and all those who were lucky to know this terrific young woman.”

Her family couldn’t immediately be reached for comment Thursday evening.

In dispatch recordings, emergency responders said they were administering CPR to one person and that one person had sustained head injuries.

The passengers were taken by ambulance to Massachusetts General Hospital, authorities said.

They were being treated for injuries that are not life-threatening, officials said.

In a statement, Suffolk District Attorney Kevin Hayden extended his “deepest sympathies to the family and friends of Elizabeth Dankert and I assure them that all aspects of this tragedy are under investigation.”

“I want to thank EMS personnel and other first responders for their exceptional treatment and recovery work under extremely difficult conditions,” he said.

The boat is a Key West brand center console recreational fishing boat with two Yamaha motors. The center console was heavily damaged in the crash.

One of the people on board was able to make a 911 call on their phone, according to dispatch recordings.

“Caller is stating that a boat crashed into them, a friend is bleeding out, not responding,” a dispatcher from the Massport Fire Department said. “Caller states [that] boat’s on top of them.”

But emergency responders searched the area and did not find evidence of a second vessel.

“At this time, it does seem like this is a single vessel incident,” the Massport commander at the scene reported shortly before midnight.

Massport shut down traffic on Runway 4R from around 11 p.m. Wednesday until 7 a.m. Thursday, spokeswoman Jennifer Mehigan said by email. Airport operations were not impacted during the closure.

James Borghesani, a spokesperson for Hayden’s office, wouldn’t say whether anyone would be facing charges in connection with the crash, citing the investigation.

John R. Ellement can be reached at john.ellement@globe.com. Follow him @JREbosglobe. Shannon Larson can be reached at shannon.larson@globe.com. Follow her @shannonlarson98.