The Senate Sergeant-at-Arms office warned staffers Tuesday of a recent spate of carjackings on Capitol Hill, sending out an e-mail with “crime prevention tips.—Since Sept. 1, there have been 22 carjackings in the area “just east of Capitol Hill,— with 16 occurring in the northeast quadrant, according to the e-mail. Most happened on Saturdays and Sundays between 10 a.m. and 7:30 p.m.“The suspects typically operate in two groups of two individuals, described as African American males between the ages of 14-25 years of age, on foot and targeting lone victims who were arriving home and were in the process of removing their personal belongings from their car,— the e-mail states. “The suspects have targeted sedans of no specific make or model.—The Metropolitan Police Department is investigating the carjackings, while the Capitol Police are “watching this closely and assisting MPD when applicable.— “While these crimes are not occurring in the primary jurisdiction of the United States Capitol Police (USCP), they are being committed in surrounding areas of Capitol Hill where some of you live, park, shop, or may otherwise visit,— the e-mail states.The Senate Sergeant-at-Arms office recommends that staffers park only in well-lit areas, immediately lock the doors after they are in their cars and to “remain alert and attentive to your environment.— Pedestrians should to stick to well-traveled streets, keep their wallets in their front pockets and ask a police officer or friend to escort them to their car if it is late at night.Despite the recent uptick of carjackings in the immediate Capitol Hill area, the 1st district — which includes Capitol Hill and Chinatown — saw fewer stolen autos this past year than in the previous year, according to preliminary statistics on the MPD Web site.