CLIFTON PARK — A blood test on a 22-year-old college student involved in a crash that killed two Shenendehowa High School students last Saturday did not indicate a high enough level of alcohol in his system for police to charge him with driving while intoxicated, according to two people briefed on the investigation.

One of the individuals, who is not authorized to comment publicly on the evidence, said the result of the alcohol test was "very low."

The test results were returned by a State Police laboratory on Thursday but not made public by State Police or Saratoga County District Attorney James A. Murphy III. But the results prompted the law enforcement officials to issue a joint statement saying they "have chosen to postpone any charging decisions and have asked the NYSP Crime Lab to continue testing the blood sample for other substances, as they would in any investigation."

The blood sample is being tested for the presence of any drugs, including cocaine or marijuana, law enforcement officials said. The test results could be returned by the end of next week.

A day after the crash, State Police said an alcohol breath test performed on Dennis Drue of Halfmoon showed that he had some alcohol in his system when his vehicle allegedly rear-ended an SUV carrying four people Saturday on the Northway, about a mile north of the Twin Bridges. State Police said their preliminary investigation indicated Drue may have been at fault in the crash that killed 17-year-olds Deanna Rivers and Chris Stewart and severely injured Stewart's girlfriend, Shaker High School student Bailey Wind, 17, and Matthew Hardy, 17, who attended Shenendehowa with Rivers and Stewart.

Any decision on whether to file criminal charges against Drue will be made after the investigation is completed, Murphy said.

Drue was driving north when, police said, he shifted across three lanes and his Volvo struck the back of Stewart's Ford Explorer. Police estimated that Drue may have been traveling about 70 to 75 mph, which is above the posted speed limit of 55 mph.

Stewart lost control of his SUV and the vehicle rolled several times into a median, ejecting Rivers and partially ejecting Hardy.

Drue's attorney, Stephen R. Coffey of Albany, said his client told him that he was not driving aggressively or intoxicated.

"I'm not surprised with the statement of the district attorney; I don't know what they've got," Coffey said. "I've thought before that it would not come back at a higher level, and I don't know (the level) for sure, only the district attorney knows, but now I'm beginning to think even more strongly that that test is not supporting alcohol as a contributing factor."

A person familiar with Drue's account said he had eaten dinner at a Colonie restaurant with a friend before the crash and had consumed two drinks. It's unclear whether police have verified that information. Coffey said Drue is 6 feet, 2 inches tall and weighs just under 150 pounds.

Drue was given two alcohol breath tests at the scene of the crash on Saturday night, and both indicated then that he had alcohol in his system, according to a law enforcement official briefed on the results. One of the tests showed Drue had alcohol in his system below the level of DWI. The second test indicated, the person said, a level of alcohol closer to the threshold for DWI — which is 0.08.

A test that indicates a person's blood-alcohol level is 0.05 or below is evidence that a person is not impaired or intoxicated, according to state law.

If a blood sample is taken more than an hour after a crash, police and prosecutors sometimes rely on doctors or other experts to estimate the amount of alcohol that may have been in the person's bloodstream at the time of an incident.

Peter Gerstenzang, a criminal defense attorney who specializes in DWI cases, said that if the blood test shows Drue's blood-alcohol level was below the legal threshold for driving while intoxicated, he could still face a charge of criminally negligent homicide, depending on any other evidence gathered by police and prosecutors, including witness accounts, an accident reconstruction and the observations of troopers at the scene.

"If the test is too low to be prosecuted as a case of driving while intoxicated, then the next thing that they would look at would be the issue of criminal negligence," Gerstenzang said. "The problem is that criminal negligence requires a high degree of negligence that is much greater than that associated with a normal accident. People cause accidents every day by violating the vehicle and traffic law, by inattention and those matters are handled civilly. To get to the level of criminal negligence, you have to have conduct that is a gross deviation from the normal standard of behavior."

Wind was released Wednesday from Albany Medical Center Hospital. Hardy was released Thursday, Albany Med confirmed.

Murphy and State Police Capt. Steven James did not put a timetable on when the accident reconstruction would be completed. They said the crime lab is expediting the drug testing on Drue's blood.

"It is important for us to allow the lab to do a thorough investigation rather than one that is based on artificial timetables," Murphy said.

Earlier Thursday, mourners packed St. Edward the Confessor Church in Clifton Park for Rivers' funeral. Burial followed in St. Paul's Cemetery in Mechanicville. Stewart's funeral is Saturday.

State Police initially said they expected to charge Drue with vehicular manslaughter or criminally negligent homicide. Now, it remains unclear if the case will be presented to a grand jury or if either of the charges will be filed.

"This is a very serious and very significant case, and something of this magnitude you would expect that the district attorney and the State Police would proceed with a great deal of care and caution in order to insure that everything is done right," Gerstenzang said. "It could turn out that it's just an accident, with horrendous consequences, but just an accident."