Gunmen on Friday shot and killed Joan Wells Root, 69, the daughter of a colonial-era British settler, in her bed at her home in the town of Naivasha, about 90 kilometers (55 miles) northwest of Nairobi. She was raised and had lived there for many years promoting environmental causes.

"We have two more suspects in custody, whom we believe have some crucial information," said Naivasha police commander Simon Kiragu.

Police suspected revenge was the motive of the killing.

"We suspect the motive of the murder was revenge and that is why we are holding an ex-employee and a poacher, who had clashed with the deceased on several occasions," he added.

On Saturday, police arrested two suspects after a sniffer dog followed their scent from the Root's compound to a village where they were hiding.

Police were also carrying out forensic tests on the clothes of the suspects arrested Saturday, Kiragu said.

"We have taken some clothes from the two suspects to the government chemist for tests as experience has shown that gunpowder could have been left on their clothes after shooting at close range," Kiragu explained.

Root, the daughter of Edmund Thorpe, a coffee farmer and photo safari guide who moved to Kenya in 1929, was well-known in Naivasha for her conservation efforts and kept several species of animals, including waterbucks, dik diks and birds, on her compound where hippos were known to gather, residents said.

Naivasha has been rife with animosity between foreign investors, mainly flower farmers, and the local population over access to resources, and has been the scene of violent attacks on European residents, although Root's murder is the first in several months.

At least three other Europeans have been slain in violent robberies in the Rift Valley since September 2004, prompting great unease and major security fears in the community.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.