Federal prosecutors are investigating a Racine, Wis., acouple for allegedly draining more than $27,000 from the campaign fund of Rep. Les Aspin (D-Wis.).

The U.S. attorney's office in Milwaukee started the investigation of Robert and Brigitta Sura, Aspin's long-time campaign chairman and treasurer, last month after Aspin complained about what he termed "significant irregularities" in the account.

A review of recent reports of the "Friend of Les Aspin Committee" shows a $9,600 in expenditures to Robert Sura this year for "services and expenses" in elections back to 1972. The amounts had been carried as debts.

The FEC reports also show $9,000 in payments to Brigitta Sura this year for the same type of services in past campaigns.

Payments totaling $8,850 for "office rent" to the R & B Property Account, at the Sura's home address, were also recorded in the campaign reports over the last half of 1977.

The Suras declined to offer explanations for the payments in a recent telephone interview. Aspin also declined comment except to say that the Suras had acted as unpaid volunteers on his past campaigns.

In a statement released by his office, Aspin said that he had noticed discrepancies in what he believed was in his campaign account over the Memorial Day weekend. A later check of the FEC reports then uncovered "a number of questionable expenditure entries," he said.

The congressman then asked U.S. Attorney John Kessler in Milwaukee to investigate and federal prosecutors reportedly subpoenaed records from the Suras.

Sura wrote Aspin in early April to say he was moving to a new job in Chicago and had to resign from his campaign duties. He said he was sending a check for the balance in the fund-raising committee's records later, according to a copy of the letter on file at the FEC.

Aspin, who said he thoughts he had about $30,000 in the bank, received a check for $620,89. The records never arrived.

With a reelection campaign facing him and $620 in his account, Aspin said: "I've got to raise some money."