By Kirstin Ridley

LONDON (Reuters) – Britain’s Serious Fraud Office (SFO) on Thursday said it had closed its four-year criminal investigation into the UK subsidiaries of KBR Inc, a U.S.-listed engineering, procurement and construction company.

“The evidence in this case did not meet the evidential test as defined in the code for crown prosecutors,” the investigator and prosecutor said in a brief statement.

KBR, which has said previously that it was cooperating with investigators, was not immediately available for comment.

The decision is the latest in a string of lengthy, major investigations shut by SFO head Lisa Osofsky. Inquiries into British American Tobacco, aero engine maker Rolls-Royce and drugs company GlaxoSmithKline have also been dropped over the past two years.

The SFO’s investigation into KBR’s British businesses, its officers, employees and agents was taken all the way to the UK Supreme Court in February.

In a judgment that dealt a blow to the agency’s abilities to gather evidence from overseas suspects, senior judges ruled that the SFO had no powers to compel foreign companies to hand over documents during an investigation. However, it confirmed the agency’s power to compel UK companies to repatriate documents held overseas.

The SFO said the ruling had no bearing on its decision to close the KBR investigation.

The case was originally related to a separate bribery inquiry into Monaco-based oil and gas consultancy Unaoil.

Unaoil’s former chief executive and chief operating officer, Cyrus and Saman Ahsani, in 2019 pleaded guilty in the United States to being part of a 17-year scheme to pay millions of dollars in bribes to officials in the Middle East, Africa and Central Asia.

In Britain, four former executives have been convicted of bribery to secure contracts worth $1.7 billion for blue-chip clients Unaoil and Western.

(Reporting by Kirstin Ridley; Editing by David Goodman)