Drug and Violent Crime Sentencing Act of 1984 - Amends the Controlled Substances Act to increase the penalties for trafficking in large amounts of controlled substances. Provides for a mandatory prison term of life for an offense involving ten or more kilograms of a controlled substance in schedule I or II.

Provides for a mandatory life sentence or the death penalty for any person who commits a murder during the production or trafficking of an illegal controlled substance. Establishes procedures for imposing the death penalty. Amends the Controlled Substances Import and Export Act to increase the penalties for trafficking in large amounts of controlled substances in Schedule I or II.

Amends the Comprehensive Drug Abuse Prevention and Control Act of 1970 to establish general criminal forfeiture provisions for drug offenses. Includes provisions relating to property subject to forfeiture, third party transfers, asset substitution, pre-indictment orders, and disposition of property. Creates a rebuttable presumption of forfeitability of certain property.

Authorizes a court to issue a warrant authorizing the seizure of property subject to forfeiture in the same manner provided for a search warrant if other injunctive relief would not assure the availability of the property.

Provides that a criminal forfeiture proceeding shall stay any civil forfeiture proceeding with respect to the same property.

Sets forth procedures for an ancillary hearing to resolve third party claims.

Makes it unlawful for any person to invest the profits of drug violations.