RIO DE JANEIRO/SAO PAULO (Reuters) - Federal police in Brazil are investigating possible money laundering in a case related to the airport seizure of wrist watches valued at some $15 million from the vice-president of Equatorial Guinea in September.

In a statement, the police said they had carried out seven search warrants in two states, including in the capital Brasilia, and in Sao Paulo, Brazil’s largest city.

While the police did not explicitly name the target on Wednesday, they said the searches were part of the same investigation as an operation in September when they seized $1.4 million and 20 diamond-studded watches valued at $15 million belonging to Teodoro Nguema Obiang at an airport near Sao Paulo.

As part of the police operation announced on Wednesday, authorities said they were also investigating the purchase of a luxury duplex apartment in an upscale Sao Paulo neighborhood.

“The apartment was acquired ... for 15 million reais ($4.02 million). Investigations indicate that the apartment was acquired by a company with 10 million reais in capital, belonging to the subject of the investigation,” police said.

Reuters was not immediately able to locate Teodorin, as Obiang is widely known. In September, the government of Equatorial Guinea denounced the seizure and said that the cash and watches were meant to cover the cost of the trip.

The government also said in a statement that Brazilian authorities had misrepresented “the true sum of the money and the value of the confiscated jewels,” and called for the confiscated assets to be returned.

Obiang, who is the son of Equatoguinean President Teodoro Nguema Obiang Mbasogo, has attracted the attention of prosecutors in the United States and France in recent years.

Last October, million of euros of assets belonging to Teodorin were ordered seized by a French court that found him guilty in absentia of using money plundered from his country to buy property and luxury cars.

The Paris court found Obiang, 48, guilty of embezzlement, and ordered the confiscation of more than 100 million euros worth of his French assets. He denied the charges.

In that trial, the court scrutinized his residence in Paris, which he bought for 25 million euros ($28.8 million) in 2005. It has 101 rooms, a gym, a hair-dressing studio and a disco.