>> David: ALL RIGHT, OUR THANKS TO YOU, PIERRE, AND OUR TO YOU, PIERRE, AND OUR INVESTIGATIVE TEAM TONIGHT. INVESTIGATIVE TEAM TONIGHT. >>> WE CONTINUE HERE, AND >>> WE CONTINUE HERE, AND TONIGHT, POLICE IN VIRGINIA SAY TONIGHT, POLICE IN VIRGINIA SAY THEY STOPPED A POTENTIAL MASS THEY STOPPED A POTENTIAL MASS SHOOTING AT A CHURCH WITH JUST SHOOTING AT A CHURCH WITH JUST MOMENTS TO SPARE. MOMENTS TO SPARE. THEY SAY THE SUSPECT WAS IN THE THEY SAY THE SUSPECT WAS IN THE CHURCH VESTIBULE WITH THE CHURCH VESTIBULE WITH THE CONGREGATION INSIDE. CONGREGATION INSIDE. HERE'S ABC'S ALEX PRESHA HERE'S ABC'S ALEX PRESHA TONIGHT. TONIGHT. >> Reporter: TONIGHT, POLICE SAY >> Reporter: TONIGHT, POLICE SAY THEY FOILED A POTENTIAL MASS THEY FOILED A POTENTIAL MASS SHOOTING AT A VIRGINIA CHURCH SHOOTING AT A VIRGINIA CHURCH WITH JUST MOMENTS TO SPARE. WITH JUST MOMENTS TO SPARE. >> THIS WAS A THWARTED >> THIS WAS A THWARTED DIABOLICAL PLOT TO KILL DIABOLICAL PLOT TO KILL CHURCHGOERS IN HAYMARKET, CHURCHGOERS IN HAYMARKET, VIRGINIA. VIRGINIA. >> Reporter: AUTHORITIES SAY >> Reporter: AUTHORITIES SAY 35-YEAR-OLD RUI JIANG STAKED OUT 35-YEAR-OLD RUI JIANG STAKED OUT THE PARK VALLEY CHURCH ABOUT THE PARK VALLEY CHURCH ABOUT 40 MILES WEST OF WASHINGTON 40 MILES WEST OF WASHINGTON D.C., EARLY SUNDAY MORNING, AND D.C., EARLY SUNDAY MORNING, AND POSTED THREATENING MESSAGES ON POSTED THREATENING MESSAGES ON SOCIAL MEDIA. SOCIAL MEDIA. AROUND 7:40 A.M., A CONCERNED AROUND 7:40 A.M., A CONCERNED COMMUNITY MEMBER CALLING IN A COMMUNITY MEMBER CALLING IN A TIP TO POLICE WHO IMMEDIATELY TIP TO POLICE WHO IMMEDIATELY STARTED SEARCHING FOR THEIR STARTED SEARCHING FOR THEIR SUSPECT. SUSPECT. >> WHAT SHE SAW CONCERNED HER >> WHAT SHE SAW CONCERNED HER ENOUGH TO CALL THE POLICE ENOUGH TO CALL THE POLICE DEPARTMENT AND SAY, "HEY, I DEPARTMENT AND SAY, "HEY, I THINK SOMETHING REALLY BAD IS THINK SOMETHING REALLY BAD IS GOING TO HAPPEN." GOING TO HAPPEN." >> Reporter: AN OFFDUTY >> Reporter: AN OFFDUTY OFFICER, WORKING SECURITY AT THE OFFICER, WORKING SECURITY AT THE CHURCH, HEARD THE CALL, AND CHURCH, HEARD THE CALL, AND QUICKLY APPREHENDING JIANG IN QUICKLY APPREHENDING JIANG IN THE CHURCH VESTIBULE. THE CHURCH VESTIBULE. THE CONGREGATION ALREADY INSIDE. THE CONGREGATION ALREADY INSIDE. >> WE PUT OUR HANDS ON HIM >> WE PUT OUR HANDS ON HIM LITERALLY IN THE NICK OF TIME. LITERALLY IN THE NICK OF TIME. >> Reporter: OFFICIALS ARRESTING >> Reporter: OFFICIALS ARRESTING JIANG LESS THAN THREE HOURS JIANG LESS THAN THREE HOURS AFTER THAT INITIAL TIP, SAYING AFTER THAT INITIAL TIP, SAYING HE WAS HEAVILY ARMED WITH A HE WAS HEAVILY ARMED WITH A LOADED HANDGUN AND ADDITIONAL LOADED HANDGUN AND ADDITIONAL MAGAZINES AND TWO KNIVES. MAGAZINES AND TWO KNIVES. POLICE ALSO DISCOVERING POLICE ALSO DISCOVERING DISTURBING WRITINGS IN HIS HOME. DISTURBING WRITINGS IN HIS HOME. THE PASTOR TELLING ABC AFFILIATE THE PASTOR TELLING ABC AFFILIATE WJLA -- WJLA -- >> IT WAS THE CLASSIC EXAMPLE OF >> IT WAS THE CLASSIC EXAMPLE OF PEOPLE THAT SAW SOMETHING SAID PEOPLE THAT SAW SOMETHING SAID SOMETHING. SOMETHING. >> Reporter: DAVID, POLICE SAY >> Reporter: DAVID, POLICE SAY THIS SUSPECT HAS NO KNOWN THIS SUSPECT HAS NO KNOWN CONNECTION TO THIS CHURCH, AND CONNECTION TO THIS CHURCH, AND TONIGHT, HE IS CHARGED WITH TONIGHT, HE IS CHARGED WITH THREATS OF BODILY HARM AND THREATS OF BODILY HARM AND CARRYING A DANGEROUS WEAPON INTO CARRYING A DANGEROUS WEAPON INTO A RELIGIOUS PLACE OF WORSHIP. A RELIGIOUS PLACE OF WORSHIP. DAVID?