The Maryland General Assembly, completing an emergency session called 11 days ago to contend with the state's savings and loan crisis, approved legislation tonight that facilitates two separate investigations of the troubled industry.

Gov. Harry Hughes, who convened the legislature after reports of management changes and possible criminal misconduct at the Old Court Savings and Loan Association of Baltimore sparked a heavy run on deposits at some of the 102 state-chartered thrifts, signed into law tonight three bills intended to determine culpability for the crisis.

The bills authorize a $500,000 study by a yet-to-be-named special counsel into the causes of the crisis and ways to prevent its recurrence, and give Attorney General Stephen H. Sachs new power to conduct a criminal investigation of Old Court that was authorized by Hughes in early May.

Enactment of the legislation completed a political compromise forged over the weekend by Hughes and legislative leaders in response to both a public clamor to root out who was responsible for the recent chain of events and political pressures to dilute the political advantage that gubernatorial candidate Sachs, a Democrat, might gain from his criminal probe.

Despite scattered grumbling that the state's taxpayers should not have to pay $500,000 merely to extricate the assembly from a political thicket, most legislators agreed that the appointment of a special counsel to study the state's role in the crisis was a necessary step toward renewing public confidence in the industry and in the government that regulates it.

Some legislators who support two other likely gubernatorial candidates -- House Speaker Benjamin L. Cardin and Baltimore Mayor William Donald Schaefer -- had been working openly since last week to derail legislation that would give Sachs the power to grant immunity from prosecution to witnesses in the Old Court investigation.

Under the legislation that was signed by Hughes tonight, Sachs gets authority for two years to grant immunity in the Old Court probe, but a separate investigation of the crisis will be conducted by a special counsel, who Hughes promised will be "a totally independent and disinterested person."

Though the governor rejected any suggestion that the package of legislation represented a delicate political compromise, many legislators disagreed.

"It's all politics," said Del. Michael R. Gordon (D-Montgomery). "If the speaker and attorney general weren't running for governor we wouldn't be here to spend $500,000. What we are telling the taxpayers of this state is, we don't have any faith in our attorney general . . . . Any other time there'd be no question about giving Sachs the powers he wants."

"It's much ado about nothing," agreed Sen. Arthur Dorman (D-Prince George's). "I think this special counsel is Mickey Mouse stuff. The state has ways of dealing with this problem. We've shown that."

The special counsel, whom Hughes is to name by June 15, is empowered to "investigate all aspects" of the savings and loan crisis touched off May 8 by reports of management problems and possible wrongdoing at Old Court, including the responsibility of various state officials, regulators, thrift industry officers and officials in the Maryland Savings-Share Insurance Corp., which formerly insured the 102 state-chartered thrifts.

Should the investigation, which is to end next March, uncover evidence of criminality, the counsel is to make a confidential report to the governor, who would refer the allegations to "the appropriate prosecutor."

The legislature, which has met three times since being called into emergency session May 17, adourned following passage of the three bills tonight. It initially enacted seven bills granting Hughes emergency powers to regulate the industry and forcing all state-chartered thrifts into either a federal insurance program or a newly created state-backed insurance agency. That legislation was part of a broad state response to the crisis that included the imposition by Hughes of a $1,000 per month limit on withdrawals, which has since been lifted from 55 of the thrifts.

Enactment of the three bills tonight was a substantial victory for Sachs, who appeared last week to have little chance of getting the legislature to beef up his legal arsenal, despite his testimony that the power to grant immunity would be a powerful tool in uncovering wrongdoing. The Old Court investigation, which Sachs said will also include federal prosecutors from the U.S. attorney's office, will guarantee the attorney general considerable public exposure well into the 1986 gubernatorial campaign.

Sachs welcomed the idea of a special counsel on Monday, saying the probe into the crisis' origins and suggestions on how to prevent a repetition would not impinge on his criminal investigation.

"You need an investigation either by the special counsel or the General Assembly," said Sen. Stewart Bainum Jr. (D-Montgomery). "I think we have to have that, and $500,000 is money well spent if it is done right. It's necessary to have somebody that has the confidence of the public to do a systematic investigation of what went wrong."

Initial speculation on who would serve as the special counsel centered on former U.S. Attorney General Benjamin Civiletti, but Hughes conceded tonight that Civiletti's partnership in the Baltimore law firm that represented MSSIC might dictate another choice.

Though Hughes said Civiletti is "the type of person you look for -- he has the knowledge, experience and integrity," the governor said the former Carter administration Cabinet officer "might agree" that his association with the firm of Venable, Baetjer and Howard constitutes a conflict.