The order should be modified on the law and the facts to deny the defendants’ motion to suppress the evidence obtained as a result of the arrest, and as so modified, affirmed. The affidavit in support of the search warrant failed to state the underlying circumstances, and hence there is no factual basis therefor. (People v. Hendricks, 25 N Y 2d 129.) The District Attorney commendably and properly consented to the vacatur of the warrant. Nevertheless, the record establishes probable cause for the arrest of the defendants and the search incident thereto which yielded the evidence sought to be suppressed.
The District Attorney was entitled to sustain the arrest and search on evidence of the investigation of the police and their observations made on and prior to the date of the arrest, January 23, 1970. (People v. Malinsky, 15 N Y 2d 86, 96.) The evidence establishes that defendants, Beverly Massey and Naomi Bostick, during October, 1969 became subjects of investigation of the Special Investigation Unit of the Police Department which has jurisdiction of crimes involving narcotics. Said defendants resided at Apartment 2E, 866 Elsmere Place, Bronx County. After surveillance, on October 29, 1969, at Apartment 30, 1764 Walton Avenue, Bronx County, Naomi Bostick and others were arrested. Naomi was arrested by Detective Joseph Strano. She then had in her possession 75 glassine envelopes of narcotics and was engaged in an operation described as a “mill”. This involved the dilution of about one pound of heroin and packaging in glassine envelopes. During the days preceding January 23, 1970, Detective Strano *182was in receipt of confidential information that a packing mill was to be put in operation on January 23, 1970 at Apartment 3H, 1874 Loring Place, Bronx County, which would involve activity by defendants Naomi Bostick and Beverly Massey. On the basis of such information, Strano on January 21, 1970 followed Beverly Massey from Elsmere Place to 1874 Loring Place, Bronx County. On January 23, 1970, commencing at 6:00 a.m., a number of detectives and policemen were stationed at and near 1874 Loring Place and 866 Elsmere Place. It had been ascertained that Apartment 3H of 1874 Loring Place was leased to one Tessie Truehart.
On January 23, 1970, the police observed many females, later fixed at 13, and males, entering 1874 Loring Place. Among them were defendants Beverly Massey and Naomi Bostick, and several females who had been observed by the police at 866 Elsmere Place, including defendants Marcelle Thomas and Robbie Taylor. At about 8:00 a.m., a Buick automobile with a New Jersey registration arrived and parked opposite 1874 Loring Place. The operator, a male, walked to the rear of the car and waited a few moments. At about 8:05 a.m., defendant Beverly Massey emerged from 1874 Loring Place, approached the Buick and engaged the operator in conversation. The operator opened the trunk and removed a cardboard box, a paper shopping bag and a valise which they carried across the street into 1874 Loring Place. Police had passed by and stationed themselves outside Apartment 3H and heard the voices of numerous females and names which had become familiar to them in the course of their investigation. At about 10:30 a.m., Naomi Bostick appeared at the premises with two shopping bags, was met by another female, and they both entered the building and the apartment.
Detective Strano testified as an expert on the packaging of narcotics the procedure observed was usually followed in the operation of a “ mill ’ ’; the practice being to gather girls involved in the process at the apartment selected for the operation ‘ ‘ before the junk got there ’ ’; that it is customary for the girl who ran the mill to meet the messenger bearing the narcotics. In this case, the girl was Beverly Massey.
It was the expert opinion of the police that prior to 1:00 p.m. on January 23, 1970, the mill was in full operation in Apartment 3H at 1874 Loring Place. Thereupon, they effected simultaneous entry through a window off a fire escape and a hallway door of the apartment. The entry exposed the defendants engaged in packaging 10 pounds of heroin, with paraphernalia *183customarily used in such an operation. The defendants did not adduce any evidence.
Probable cause for the arrest and search here involved is that which would satisfy a reasonable, cautious and prudent police officer, with the knowledge, experience and expertise of the arresting officers. (People v. Valentine, 17 N Y 2d 128, 132.) The evidence clearly demonstrates a pattern of behavior and procedure followed by those engaged in the packaging of narcotics for users, including the employment of females involved in the traffic of drugs, their attendance at a selected site in advance of the delivery of the drugs involved, the delivery of the narcotics to Beverly Massey, the person in charge of the girls, and its immediate packaging. The concurrence of these events, in the opinion of one well versed in drug traffic, is hardly consistent with innocent or lawful activity. Here involved is abnormal activity, highly suspicious involving persons known to be engaged in the traffic of drugs reinforced by prior information of a packing mill. (People v. Munger, 24 N Y 2d 445, 452.) The informer’s communication, in my opinion, together with the observations of the officers, established probable cause. (People v. Smith, 21 N Y 2d 698, 700.)