Suspected spam supremo Christopher Smith, nicknamed the Rizler, will appear in court today after being arrested in a midnight operation at a Minneapolis airport.

Smith was apprehended shortly after stepping off a flight from the Dominican Republic, where he had been operating since a US federal judge in May shut down his companies, Burnsville Internet and Xpress Pharmacy Direct, and ordered him to stop selling drugs online.

Smith had since set up similar operations in the Dominican Republic, through which he is alleged to have sent more than a billion spam emails either to AOL email addresses or through AOL email accounts.

The FBI claims that Smith has already made about $18m this year.

The law enforcement agency said that the 25 year-old had flown to the Dominican Republic under a false passport and used a cash card to obtain money from a bank account after his own had been seized by a court order.

His wife Anita, his Minnesota girlfriend and several others brought him thousands of dollars in cash.

Federal authorities raided Xpress Pharmacy and Smith's home on 10 May, seizing his passport and $4.2m in assets, including a $1.1m house and luxury cars worth $1.8m. At the same time the FBI closed down his 85-employee company.

Investigators concluded that Smith had been selling medicines to customers without proper prescriptions, and selling drugs without a licence. Four days after he appeared in a federal court he fled for the Dominican Republic, according to the US Attorney's office.

The US Attorney's office claims that Smith had broken court orders and is recommending that he be held in criminal contempt and jailed for six months.

Court documents allege that by 21 June, Smith had used aliases to set up new websites and was selling drugs without prescriptions online and through a new call centre he had set up in the Dominican Republic.

"There are huge profits to be made from spam, and organised criminals are prepared to break many laws in their greed for money," said Graham Cluley, senior technology consultant at Sophos.

"Smith has been one of the most notorious spammers, and anyone who has been deluged with spam offering medication and drugs will welcome the US authorities making progress in this case."