(Corrects paragraph 4-5 to show that Juergen Steinemann is on the board of Barry Callebaut and Lonza, not Pieter Boone.)
* Probe targets supervisory board chairman and top executive
* Centres on stock buys ahead of announced Metro demerger
* Metro says no insider information available at that time
DUESSELDORF, Germany, Nov 3 (Reuters) - German prosecutors are investigating the supervisory board chairman and a senior executive of retailer Metro on suspicion of insider trading, the company said on Friday.
Police and prosecutors searched Metro's offices in the western German city of Duesseldorf on Friday, a spokesman for Metro said, adding the group was cooperating with the authorities.
The investigation centres on how much supervisory board Chairman Juergen Steinemann and Chief Operating Officer Pieter Boone knew about Metro's plans to split in two when they bought shares in the company in February 2016, around a month before the company made any official announcement.
A regulatory filing shows that Steinemann, who is also on the board of directors at Switzerland's Barry Callebaut and Lonza, bought 43,000 shares in Metro on Feb. 22, 2016, worth just over 1 million euros ($1.2 million) at the time.
Boone purchased 2,175 shares on Feb. 26, 2016, a separate filing shows.
Metro announced on March 30, 2016 that it planned to separate its wholesale and food business from its consumer electronics chain to help each focus and grow faster, sending its stock 12 percent higher.
The consumer electronics business is now listed on the stock exchange under the name Ceconomy.
"Metro communicated news of the planned split-up of the company on March 30, 2016 in a timely fashion and in accordance with the relevant rules and thereby fulfilled all its obligations," the spokesman for Metro said.
"At the time that Mr. Steinemann and Mr. Boone bought shares, no insider information was available," he added.
The Duesseldorf prosecutor's office said it would not comment on the investigation, first reported by German weekly Spiegel, before making a statement on Monday.
Shares in Metro were down 1.3 percent at 16.43 euros by 1559 GMT on Friday, underperforming a 0.5 percent higher German mid-cap index.
Financial watchdog Bafin, which prompted the prosecutor's investigation, declined to provide details on what had raised its suspicion.
It routinely follows up on any unusual share price movements and related stock purchases. Last year, it reported suspicion of insider trading 21 times to public prosecutors.
The most recent case that made headlines in Germany was an insider trading probe of Deutsche Boerse Chief Executive Carsten Kengeter, who resigned last month amid continuing allegations - which both Kengeter and Deutsche Boerse say are unfounded.
$1 = 0.8581 euros Reporting by Matthias Inverardi; Writing by Maria Sheahan; Editing by Keith Weir and Elaine Hardcastle